PHYSIOLOGY / ANATOMY / GROWTH AND AGING

Adams, M. A., and P. E. Nachtigall. 1989. Chemical Communication in Dolphins: Chemical Constituents of the Perianal Gland (Abstract). Abstracts of the Eleventh Annual Meeting of the Association for Chemoreception Sciences (AChemS XI), Sarasota FL. Chem. Senses 14(5):681.

Samples of perianal gland secretions were collected from male Tursiops. Combined gas chromatography-mass spectrometry analysis identified several long-chain organic acids in the samples. The possibility of chemically mediated behavior in dolphins is discussed.

Bello, M. A., R. R. Roy, T. P. Martin, H. W. Goforth, Jr., and V. R. Edgerton. 1985. Axial Musculature in the Dolphin (Tursiops truncatus): Some Architectural and Histochemical Characteristics. Mar. Mamm. Sci. 1:324-336.

In view of reports that dolphins can swim faster than would be predicted based on physical features and presumed muscle power, this study examined muscle fiber types, fiber sizes and tendon arrangements of the dorsal and ventral axial muscles.

Brown, W. R., J. R. Geraci, B. D. Hicks, D. J. St. Aubin, and J. P. Schroeder. 1983. Epidermal Cell Proliferation in the Bottlenosed Dolphin (Tursiops truncatus). Canadian Jour. Zool. 61:1587-1590.

Using a radioactive labeling technique, the authors found that Tursiops has a large proliferative capacity which contributes to the unusual thickness of the skin.

Ceruti, M. G. 1983. Chemical Characteristics of Compounds Released by Marine Mammals. NOSC TR 930, 52 pp.

Excretions, secretions, and glandular extracts were analyzed to determine chemical constituents which may be involved in marine mammal chemoreception.

Ceruti, M. G., P. V. Fennessey, and S. S. Tjoa. 1985. Chemoreceptively Active Com- pounds in Secretions, Excretions, and Tissue Extracts of Marine Mammals. Comp. Biochem. Physiol. 32A:505-514.

Hypothesizing that chemical communication may occur in marine mammals and that analysis of secretions and excretions would identify some specific compounds that might be involved, the authors determined the principal chemical components of sexual secretions, urine, feces, and blood from Atlantic Tursiops. Twenty-two identified compounds in aqueous solutions of sufficient concentration could be detected gustatorily by humans.

Coulombe, H. N., S. H. Ridgway, and W. E. Evans. 1965. Respiratory Water Exchange in Two Species of Porpoise. Science 149(3679):86-88.

The exhalations of the two species of porpoises examined contained less water vapor than those of terrestrial mammals. This is seen as an adaptation to conserve water in these animals which live in an environment where no fresh water is available .

Dawson, W. W., D. A. Carder, S. H. Ridgway, and E. T. Schmeisser. 1981. Synchrony of Dolphin Eye Movements and Their Power Density Spectra. Comp. Biochem. Physiol. 68A:443-339.

Eye movements in the horizontal and vertical planes of a normal human and two bottlenosed dolphins were analyzed and compared. Although dolphin eyes are mobile at lower fundamental frequencies than in humans, there is a low level of synchrony between the two eyes.

Dawson, W. W., J. P. Schroeder, and J. F. Dawson. 1987. The Ocular Fundus of Two Cetaceans. Mar. Mamm. Sci. 3:`1-13.

By use of a technique to correct the aerial myopia encountered in fundus photography of the marine mammal eye, the first high quality photographs were obtained of the eyes of a living Tursiops and a Grampus.

Dawson, W. W., J. P. Schroeder, and S. N. Sharpe. 1987. Corneal Surface Properties of Two Marine Mammal Species. Mar. Mamm. Sci. 3:186-197.

Describes and compares the cornea of Tursiops and Zalophus. The results provide an explanation for the resolution of the Zalophus eye in air and water, but "the aerial acuity of Tursiops remains a mystery."

Demski, L. S., S. H. Ridgway, T. H. Bullock, and M. Schwanzel-Fukuda. 2985. Terminal Nerve of Odontocete Whales. Amer. Zool. 25:107A.

See Ridgway et al., 1987, of this section.

Demski, L. S., S. H. Ridgway, and M. Schwanzel-Fukuda. 1990. The Terminal Nerve of Dolphins: Gross Structure, Histology and Lutenizing-hormone-releasing Hormone Immunocytochemistry. Brain, Behavior and Evolution 36:249-261.

The structure and cell type of the dolphin terminal nerves and ganglion are described. The cells that exhibit a response to lutenizing hormone releasing hormone antibody are figured and described in detail.

Evans, W. E. 1974. Telemetering of Temperature and Depth Data from a Free-ranging Yearling California Gray Whale (Eschrichtius robustus). Mar. Fish. Rev. 36(4):52-58.

A young female gray whale, held in captivity for a year, was released carrying a radiotelemetry package that transmitted depth of dive and temperature-at-depth data .

Flanigan, N. J. 1965. Neuroanatomy of the Dolphin Spinal Cord. Anat. Rec. 151:350.

Flanigan, N. J. 1966. The anatomy of the Spinal Cord of the Pacific Whitesided Dolphin (Langenorhynchus obliquidens). In: Whales, Dolphins. and Porpoises, pp. 207-231, ed. K. S. Norris, U. of Calif. Press, Berkeley, CA.

Describes the anatomy of the spinal cord and discusses the possible significance of its distinctive features.

Flanigan, N. J. 1972. The Central Nervous System. In: Mammals of the Sea - Biology and Medicine, pp. 215-246, ed. S. H. Ridgway, Chas. C. Thomas Publ., Springfield, IL.

Reviews present knowledge of the central nervous system of cetaceans and pinnipeds, including findings made by the author while working at the Navy's Marine Bioscience Facility.

Fong, M. L., R. M. Yamada, and W. A. Friedl. 1989. Post Exercise Skin Temperature and Heat Flux of Atlantic Bottlenosed Dolphins (Tursiops truncatus). (Abstract) Abstracts of the Eighth Biennial Conference on the Biology of Marine Mammals, Soc. Mar. Mammalogy, Pacific Grove, CA., p. 20.

Skin temperatures and heat flux were measured from two dolphins before and after controlled swimming. Different temperature and flux patterns occurred for the dolphins' bodies and fins.

Friedl, W. A., P. E. Nachtigall, P. W. B. Moore, N. K. W. Chun, J. E. Haun, R. W. Hall, and J. L. Richards. 1990. Taste Reception in the Pacific Bottlenosed Dolphin (Tursiops truncatus gilli) and the California Sea Lion (Zalophus californianus). In: Sensory Abilities of Cetaceans, pp. 447-454, eds. J. A. Thomas and R. A. Kastelein, Plenum Press, New York.

Abilities to detect sour, bitter, salty, and sweet substances in distilled water were tested. The dolphin detected all four tastes. The sea lion detected salty, sour and some bitter substances but not other bitter tastes or the sweet taste (sucrose). The study showed for the first time that bottlenosed dolphins can detect sweet substances and that California sea lions have gustatory senses.

Friedl, W. A., R. M. Yamada, M. L. Fong, and J. E. Haun. 1987. Physical Conditioning of Bottlenosed Dolphins for Bioenergetic Studies. (Abstract) Abstracts of the Seventh Biennial Conference on the Biology of Marine Mammals, Soc. Mar. Mammalogy, Miami, FL., p. 23.

Describes the equipment, training, and conditioning regime for a study to determine dolphin aerobic work capacity and swimming energy requirements.

Friedl, W. A., J. E. Haun, M. L. Fang, and R. M. Yamada. 1989. Aerobic Exercise by Bottlenosed Dolphins. (Abstract) Abstracts of the Eighth Biennial Conference on the Biology of Marine Mammals, Soc. Mar. Mammalogy, Pacific Grove, CA., p. 21.

Describes measurements of oxygen consumption and respiration rate for aerobic exercise at controlled levels. Results indicated short-term oxygen debts were incurred even for conditions seemingly within the dolphins' maximal aerobic capacity.

Gilmartin, W. G., R. W. Pierce, and G. A. Antonelis, Jr. 1974. Some Physiological Parameters of the Blood of the California Gray Whale. Mar. Fish. Rev. 36(4):28-31.

Hematocrit, oxyhemoglobin dissociation curve, and blood volume were determined, the last by isotopic techniques.

Green, R. F. 1972. Observations on the Anatomy of Some Cetaceans and Pinnipeds. In: Mammals of the Sea - Biology and Medicine. pp. 247-297, ed. S. H. Ridgway, Chas. C. Thomas Publ., Springfield, IL.

Observations (with unique new illustrations) of cetacean and pinniped anatomy based primarily on dissections made by the author.

Greenwood, A. G., S. H. Ridgway. and R. J. Harrison. 1971. Blood Values in Young Gray Seals. Jour. Am. Vet. Med. Assn. 159(5):571-574.

Red and white blood cell measurements, plasma electrolytes and serum proteins, and blood chemistry values are given.

Hamlin, R. L., S. H. Ridgway, and W. G. Gilmartin. 1972. Electrocardiogram of Pinnipeds. Am. Jour. Vet. Res. 33(4):867-875.

Electrocardiograms obtained from California sea lions, elephant seals, and harbor seal are analyzed and discussed.

Harrison, R. J., and S. H. Ridgway, 1971. Gonadal activity in some bottlenosed dolphins (Tursiops truncatus). Jour. Zool., London 165:355-366.

Characteristics of the ovaries and testes of young and adult bottlenosed dolphins indicate that sexual maturity in females is probably reached in their fifth year. Males become sexually mature at an estimated age of 10 years. No evidence of regular cyclic ovulation was found.

Harrison, R. J., and S. H. Ridgway. 1972. Telemetry in Experimental and Trained Dives by Seals. Proc. Anat. Soc. Gr. Brit. and Ireland, Jour. Anat. 111(3):491.

See Harrison and Ridgway, 1972 below.

Harrison, R. J., and S. H. Ridgway. 1972. Seals, Dolphins, and Diving. New Scientist, 10 August 1972, pp. 283-285.

Describes how diving responses can be monitored by radiotelemetry.

Harrison, R. J., S. H. Ridgway, and P. L. Joyce. 1972. Telemetry of Heart Rate in Seals. Nature 238:280.

Radiotelemetry devices were implanted in the hypodermis of the neck and back of gray seals to follow heart-rate changes in unrestrained seals diving on command. Bradycardia was found to be less marked during trained dives than in previously reported forced and restrained dives.

Harrison, R. J., and S. H. Ridgway. 1975. Restrained and Unrestrained Diving in Seals. Rapp. P. -v. Reun. Cons. Int. Explor. Mer. 169:76-80.

Cardiovascular response of gray seals was much higher during a forced dive than during an unrestrained trained dive. Cardiac rhythm also varied with different observed behaviors.

Harrison, R. J., and S. H. Ridgway. 1976. Deep Diving Mammals. 51 pp. Meadowfield Press Ltd., Durham, England.

A booklet reviewing what is known about deep diving in mammals, including depth and duration of dives, historical background, adaptations, other aspects of deep diving, and future deep diving by man.

Horvath. S. M., H. Chiodi, S. H. Ridgway, and S. Azar, Jr. 1968. Respiratory and Electrophoretic Characteristics of Hemoglobin of Porpoises and Sea Lions. Comp, Biochem. Physiol. 24:1027-1033.

Porpoises that swim faster and dive longer and deeper have greater hemoglobin oxygen affinity than the slower swimming, shallower, and shorter diving species.

Hui, C. A., 1975. Thoracic Collapse as Affected by the Retia Thoracica in the Dolphin. Resp. Physiol. 25:63-70 (Netherlands).

The carcass of a Delphinus was subjected to two simulated dives in a hyperbaric chamber to the equivalent of 69.7 m. In one dive, the thorax was in natural state, in the other, 100 ml of water had been injected into each pleural cavity. Results indicated that an engorged thoracicrete reduce the displacement stress on abdominal organs under pressures encountered in diving.

Hui, C. A. 1978. Reliability of Using Dentin Layers for Age Determination in Tursiops truncatus. Report to Marine Mammal Commission. Nat'l Tech. Info. Serv. PB-288 444, 25 pp.

Discusses histology of the mammalian tooth, utility of using dentin layers for age determination, and findings from an examination of teeth from three Tursiops, two of known age. It is concluded that annual increments of dentin are visible and can be regular through 11 years. No correlation of dentin layering with food consumption patterns or innate biorythms based on lunar cycles was found.

Hui, C. A. 1979. Correlates of Maturity in the Common Dolphin (Delphinus delphis). Fish. Bull. 77:295-300.

Body weight and length, degree of bone fusion in flippers, dentine layers, testes weights, and ovarian scars in 87 D. delphis (which had died in tuna nets) were treated statistically to determine correlation with sexual maturity.

Hui, C. A. 1981. Seawater Consumption and Water Flux in the Common Dolphin (Delphinus delphis). Physiol. Zool. 54(4):430-440.

In two captive dolphins, total body water was found to be low (37 percent of total body weight), indicating a high fractional rate of water turnover, most of which is due to the permeability of the skin. Skin was shown to be impermeable to sodium, so the only sodium source is ingested sea water.

Kanwisher, J. W., and S. H. Ridgway. 1983. The Physiological Ecology of Whales and Porpoises. Sci. Am. 248(6):110-120.

Discusses the particular physiologic adaptations evolved by cetaceans for living in the sea, notably the ability to dive deep for long periods. Unlike other marine organ- isms, which tend to move nutrients downward, oceanic marine mammals, through their fecal output near the surface, tend to move nutrients upward.

Leatherwood, J. S., M. W. Deerman, and C. W. Potter. 1978. Food and Reproductive Status of Nine Tursiops truncatus from the Northeastern United States Coast. Cetology, no. 28, 6 pp.

The nine dolphins (six stranded, three entangled in a fishing net) were examined for age, reproductive status, and stomach contents. Stomachs contained a predominance of Atlantic croakers, sea trout, and spot.

Lowell, W. R., and W. F. Flanigan, Jr. 1478. Chemoreception in Marine Mammals: A Review of the Literature. NOSC TR 353, 19 pp.

Discusses anatomical and physiologicai correlates and behavioral and ecological considerations of olfaction and gustation in cetaceans, pinnipeds, sea otters, and sirenians, followed by a bibliography. (See also a later version, Marine Mammal Chemoreception, Mamm. Rev. 1053-1059, 1980.)

Malyin, R. L., J. P. Bonjous, and S. H. Ridgway. 1971. Antidiuretic Hormone Levels in Some Cetaceans. Proc. Soc. Exp. Biol. and Med. 136(4):1203-1205.

Data on renal function in the bottlenosed dolphin and killer whale are presented and discussed.

Malvin, R. L., S. H. Ridgway, and L. Cornell. 1978. Renin and Aldosterone Levels in Dolphins and Sea Lions. Proc. Soc. Exper. Biol. and Med. 157:665-668.

A significant correlation between plasma renin activity (PRA) and concentration of aldosterone in plasma was found in both dolphins and sea lions. An excellent corre- lation between urinary sodium excretion and PRA was also obtained in two dol- phins. These data support the hypothesis that in marine mammals the renin-angiotension-aIdosterone axis plays a role in the regulation of salt balance.

McCormick, J. G., E. G. Wever, J. L. Mattsson, and S. H. Ridgway. 1477. Anatomical and Physiological Adaptations of Marine Mammals for the Prevention of Diving- induced Middle-ear Barotrauma and Round Window Fistula. Undersea Biomedical Research 4(1):A 42.

Comparative marine mammal experience helped make a preoperative diagnosis of diving-induced round window fistula in a human patient.

Nachtigall, P. E., and R. W. Hall. 1984. Taste Reception in the Bottlenosed Dolphin. Acta 200. Fennica 172:147-148.

A dolphin's taste thresholds for citric acid (sour) and quinine sulfate (bitter) were found to be just above the human thresholds for these substances.

Nachtigall, P. E. 1986. Vision, Audition, and Chemoreception in Dolphins and Other Marine Mammals. In: Dolphin Cognition and Behavior, pp. 79-113, eds. R. J. Schus- terman, J. A. Thomas, and F. G. Wood, Lawrence Erlbaum Associates, Hillsdale, NJ .

A review of what is known about sensory capabilities in dolphins, pinnipeds, and sea otters (vision only).

Nachtigall, P. E. 1989. Risso's Dolphin (Grampus griseus) Vision. (Abstract) Abstracts of the Eighth Biennial Conference on the Biology of Marine Mammals, Soc. Mar. Mam- malogy, Pacific Grove, CA., p. 45.

See Nachtigall, 1989, below.

Nachtigall, P. E. 1989. Visual Acuity of the Risso's Dolphin (Grampus grtreus) in Air. (Abstract) Bulletin of the Psychonomic Society, Abstracts of the 30th Annual Meeting Psychonomic Soc., Atlanta, GA., 27(6):502.

Visual acuity, in terms of minimum angle of resolution, was measured using a two- alternative forced-choice procedure.

Nachtigall, P. E., and J. L. Pawloski. 1992. Aerial Visual Acuity of the Risso's Dolphin at Two Distances. (Abstract) Bulletin of the Psychonomic Society, Abstracts of the 32th Annual Meeting Psychonomic Sac., San Francisco, CA., November 1992, 29(6):528.

Visual acuity, in terms of minimum angle of resolution, was measured at distances of 1 and 2.5 m. Resolution was found to be better at 2.5 m than at 1 m.

Pepper, R. L., and J. V. Simmons, Jr. 1973. In-air Visual Acuity of the Bottlenosed Dol- phin. Exper. Neur. 41(2):271-276.

Horizontal-black and white-line gratings were presented in a successive discrimina- tion task. Over a constant viewing distance of 2.8 m, a minimal visual angle of 18 min. of arc was obtained.

Ridgway, S. H., and D. G. Johnston. 1966. Blood Oxygen and Ecology of Porpoises of Three Genera. Science 151(3709):456-458.

The total blood-oxygen content of the highly active, deep-diving Dall's porpoise is almost three times that of the coastal dwelling bottlenosed. The pelagic white-sided dolphin, less active than the Dall, is intermediate. Heart weight of the Dall's por- poise is about 140 percent that of the bottlenosed.

Ridgway, S. H., B. L. Scronce, and J. Kanwisher. 1969. Respiration and Deep Diving in the Bottlenosed Porpoise. Science 166:1651-1654.

A porpoise was trained to dive on command to depths down to 300 m, then provide a lung air sample at the surface before breathing. It was also trained to swim between divers at 20 m and to breath-hold at the surface for deep-dive time equiva- lents. Analyses of oxygen and carbon dioxide were then compared for the three situations.

Ridgway, S. H., J. G. Simpson, G. S. Patton, and W. G. Gilmartin. 1970. Hematologic Findings in Certain Small Cetaceans. Jour. Am. Vet. Med. Assn. 157:566-575.

Clinical laboratory data on the blood of small cetaceans were collected from repre- sentatives of a number of species.

Ridgway, S. H., and G. S. Patton. 1971. Doiphin Thyroid: Some Anatomical and Physi- ological Findings. Z. vergl. Physiol. 71:129-141.

Research conducted with representatives of four species of delphinids was directed toward elucidating the function of this organ in toothed cetaceans. Biochemical data on thyroid hormones are presented. All animals examined had larger thyroids than terrestrial mammals of comparable weight.

Ridgway, S. H. 1971. Buoyancy Regulation in Deep Diving Whales. Nature 232(5306): 133-134.

Comments on a suggestion that the spermaceti organ of sperm whales serves as a buoyancy regulator in deep dives. Evidence is preserited that this hypothesis is incor- rect.

Ridgway, S. H. 1972. Homeostasis in the Aquatic Environment. In: Mammals of the Sea Biolagy and Medicine, pp. 590-747, ed. S. H. Ridgway, Chas. C. Thomas Publ., Springfield, IL.

Account of marine mammal research conducted by the author in the areas of diving physiology, water balance, reproductive physiology, hematology, and blood chemis- try, husbandry, behavior, and animal health (including anesthesia).

Ridgway, S. H. 1973. Control Mechanisms in Diving Dolphins and Seals. Doctoral Thesis, University of Cambridge, 90 pp. with appendices.

Primarily on diving physiology of dolphins, sea lions, and seals (especially the gray seal), but also includes research on hearing, sleep, and brain temperatures in the gray seal.

Ridgway, S. H., J. G. McCormick, and E. G. Wever. 1974. Surgical Approach to the Dolphin's Ear. Jour. Exp. Pathol. 188(3):265-276.

Describes anesthesia procedure, surgical techniques, and physiological monitoring for making electrophysiological measurements at the cochlea.

Ridgway, S. H., R. J. Harrison, and P. L. Joyce. 1975. Sleep and Cardiac Rhythm in the Gray Seal. Science 187:553-555.

Brainwaves, heartbeat, and eye movements of seals sleeping underwater, on the surface, or when hauled out were recorded by radiotelemetry.

Ridgway, S. H., and P. L. Joyce. 1975. Studies on Seal Brain by Radiotelemetry. Rapp. P.-v. Reun, Cons. Int. Explor. Mer. 169:81-91.

Auditory-evoked potentials of the gray seal were used to obtain evoked response curves for auditory stimulation. Cortical-evoked response was most sensitive at 4 kHz in air and at 20-25 kHz underwater. Also includes EEG and EKG data on sleep in the gray seal, with observations of behavior.

Ridgway, S. H., D. A. Carder, and W. Clark. 1975. Conditioned Bradicardia in the Sea Lion (Zalophus californianus). Nature 256(5512):37-38.

Slowing of heart rate was achieved by conventional conditioning techniques.

Ridgway, S. H. 1976. Diving Mammals and Biomedical Research. Oceanus 19(2):49-55.

Describes biomedical research conducted with the California sea lion, gray seal, common seal, elephant seal, Weddell seal, and bonlenosed dolphin.

Ridgway, S. H., and R. H. Brownson. 1979. Brain Size and Symmetry in Three Dolphin Genera. Anat. Rec. 193:664.

Asymmetries of weight and surface area of cerebral cortex between right and left hemispheres were found in Tursiops and Delphinus, but no significant asymmetries were found in Stenella. Average body and brain weights, lengths, and cortical sur- face areas are given for 13 Tursiops, 9 Delphinus, and 11 Stenella .

Ridgway, S. H., and R. Howard. `1979. Dolphin Lung Collapse and Intramuscular Circula- tion During Free Diving: Evidence from Nitrogen Washout. Science 206:1182-1183.

Intramuscular nitrogen tensions in Tursiops after repetitive ocean dives suggested that lung collapse occurs at a depth of about 70 meters and that intramuscular circulation is maintained during unrestrained diving in the open sea. The dolphin is not protected by lung collapse in dives shallower than 70 meters.

Ridgway, S. H., T. H. Bullock, D. A. Carder, R. L. Seeley, D. Woods, and R. Galambos. 1981. Auditory Brainstem Responses in Dolphins. Proc. Natl. Acad. Sci. 78(3):1943-`1947.

Auditory brainstem response (ABR) in two Tursiops and two Delphinus were com- pared with human and rat ABR data. The ABR can be used to test theories of dolphin sonar signal processing and permits rapid evaluation of hearing thresholds. Audiometric information on stranded or trapped giant whales might be obtained by using the ABR.

Ridgway, S. H., and C. A. Fenner. 1982. Weight-length Relationships of Wild-caught and Captive Atlantic Bottlenosed Dolphins. Jour. Am Vet. Med. Assn. 181(11):1310-1315.

From weight and length measurements of 144 dolphins, guidelines were established for use in estimating whether a dolphin is over or underweight.

Ridgway, S. H., C. A. Bowers, D. Miller, M. L. Schultz, C. A. Jacobs, and C. A. Dooley. 1984. Diving and Blood Oxygen in the White Whale. Canadian Jour. Zool. 62(11):2349-2351.

White whales, trained to dive on command in the open sea, remained submerged as long as 15 min 50 sec and dove as deep as 647 m (2122 ft).

Ridgway, S. H., and R. H. Brownson. 1984. Relative Brain Sizes atld Cortical Surface Areas in Odontocetes. Acta Zool. Fennica 172:149-152.

Surface area of the cerebral cortex was found to be directly related to brain weight in a variety of odontocetes, but the genera differed greatly when cortical area and brain weight were related to body length and weight and to encephalization quotient. Includes findings on brains of neonates and on brain asymmetries.

Ridgway, S. H. 1985. The Bends Problem: Dolphins, Seals, and Nitrogen. (Abstract) Abstracts of the Sixth Biennial Conference on the Biology of Marine Mammals, Soc. for Mar. Mam., Vancouver, B. C., p. 102.

Reviews and compares findings from diving studies on dolphins and seals. Dolphin breathold time is shorter, but they dive faster and seem capable of more deep dives in rapid succession.

Ridgway, S. H. 1986. Diving Responses, Reply to R. Elsner. (Letter to the Editor) Mar. Mam. Sci. 2(4):326-328.

Discusses the so-called "diving responses." Proposes more specific terminology for the physiological processes involved.

Ridgway, S. H. 1986. Diving and Asphyxia by R. Elsner and B. Gooden. (Book Review) Mar. Mam. Sci. 2(1):82-83.

Laudatory review of a monograph on physiological adaptations to diving by verte- brates .

Ridgway, S. H. 1986. Diving Dolphins. In: Research on Dolphins, pp. 33-58, eds. M. M. Bryden and Richard Harrison, Oxford Univ. Press, NY.

Includes historical background on depth-of-dive inferences and observations, mod- ern studies, hazards of diving, respiration, bradycardia, and species differences with respect to metabolism, blood volume, and blood oxygen capacity.

Ridgway, S. H. 1986. Dolphin Brain Size. In: Research on Dolphins, pp. 59-70, eds. M. M. Bryden and R. J. Harrison, Oxford Univ. Press. NY.

Discusses absolute brain sizes in cetaceans: the various cephalization coefficient concepts, including Jerison's "encephalization quotient," here applied to cetaceans; growth of the brain; fissurization; volume of the dolphin cortex; and asymmetry of the dolphin brain.

Ridgway, S. H. 1986. Diving in Cetaceans. In: Diving in Animals and Man, pp. 33-62, eds. A. O. Brubakk, J. VCI. Kanwisher, and G. Sundness, The Norwegian Society of Science and Letters, Trondheim, Norway.

A comprehensive account, including known diving capabilities of 10 cetaceans, tech- niques used to study diving, physiological and anatomical hazards of diving, adaptations for diving, sound production and diving, metabolism and diving,'oxygen stores, and bradycardia.

Ridgway, S.H. 1987. The Cetacean Central Nervous System. In: Encyclopedia of Neuroscience, volume I., ed. by G. Adelman, Boston:Birkhauser, pp.220-225.

The author does a concise review of what is known about the cetacean central nervous system with special emphasis on anatomy and physiology.

Ridgway, S. H., L. S. Demski, T. H. Bullock, and M. Schwanzel-Fukuda. 1987. The termi- nal Nerve in Odontocete Cetaceans. Ann. New York Acad. Sci. 519:201-212.

Terminal nerves accompany olfactory nerves in many vertebrate species. Olfactory nerves are completely absent, however, in adult odontocetes, but large, myelinated terminal nerves persist. Five odontocete species were studied in detail; the terminal nerves observed were the largest ever reported. The possible chemosensory function of the terminal nerve in odontocetes is discussed.

Ridgway, S. H. 1988. The Cetacean Central Nervous System. Camparative Neuroscience and Neurobiology (Birkhauser, Boston) 1:20-25.

Current knowledge on the anatomy and physiology of the central nervous system of whales, dolphins, and porpoises is reviewed.

Ridgway, S. H. 1989. The Central Nervous System of the Bottlenosed Dolphin. In: The Bottlenosed Dolphin, Tursiops spp., pp. 69-97, eds. J. S. Leatherwood and R. Reeves, Academic Press, San Diego, CA.

Current knowledge on the brain of the bofflenosed dolphin (Tursiops truncatus) is reviewed. Photographs and drawings illustrate various features of the brain.

Ridgway, S. H., and D. A. Carder. 1990. Tactile Sensitivity, Somatosensory Responses, Skin Vibrations, and the Skin Surface Ridges of the Bottlenosed Dolphin (Tursiops truncatus). In: Sensory Abilities of Cetaceans, eds. J. A. Thomas and R. A. Kastelein, Plenum Press, New York, pp. 163-179.

The dolphin's skin sensitivity was studied through the use of electrophysiological techniques. A map of skin sensitivity is presented and skin anatomy is discussed with special consideration of the cutaneous ridges and muscle underlying the skin.

Ridgway, S. H. 1986. Physiological Observations on Dolphin Brains. In: Dolphin Cognition and Behavior, pp. 31-59, eds. R. J. Schusterman, J. A. Thomas, and F. G. Wood, Lawrence Erlbaum Associates, Hillsdale, NJ.

Discusses anatomical and physiological characteristics of dolphin brains, including size, convolutedness, cortex volume, metabolism, hemispheric independence, lateralization, and auditory areas.

Seeley, R. L., and J. N. Price. 1972. Underwater Electric Field Telemetry of Biophysical Data. Inst. Electric and Electronic Engr., Region Sir Conf. 4 pp.

Describes problems of radiotelemetry of biophysical data from marine mammals, and presents design information which provides solutions to some of these prob- lems .

Seeley, R. L., W. F. Flanigan, Jr., and S. H. Ridgway. 1976. A Technique for Rapidly Assessing the Hearing of the Bottlenosed Porpoise (Tursiops truncatus). NUC TP 522, 15 pp.

Brainwave activity was used to determine approximate auditory "threshold" levels. This rapid (4-6 hr) technique provides an estimation of the hearing ability of an unanesthetized porpoise over a frequency range of 5 to 200 kHz and could be used to screen hearing in other marine mammals.

Shoemaker, P. A. and S. H. Ridgway. 1991. Cutaneous Ridges in Odontocetes. In: Marine MammaE Science 7(1):66-74.

The authors took surface impressions of dolphin skin to quantify the tiny cutaneous ridges that run circumferentially around the body from head to dorsal fin. They suggest that the ridges may have some function in the sense of touch and in the hydrodynamic characteristics of the animal.

Simpson, J. G., W. G. Gilmartin, and S. H. Ridgway. 1970. Blood Volume and Other Hematologic Values in Young Elephant Seals (Mirounga angustirostris). Am. Jour. Vet. Res. 31(8):1449-1452.

A mean blood volume of 216 ml/kg and a mean packed cell volume of 64 percent were found. The elephant seal, with the mean blood volume representing 20 percent or more of body weight, has the highest reported blood volume of any mammal.

Simpson, J. G., and M. B. Gardner. 1972. Comparative Microscopic Anatomy of Selected Marine Mammals. In: Mammals of the Sea - Biology and Medicine, pp. 298-418, ed. S. H. Ridgway, Chas. C. Thomas Publ., Springfield, IL.

Profusely illustrated paper on the histology of organs and systems in certain cetace- ans and pinnipeds, with emphasis on pathology.

Stromberg, M. W. 1985. Fat Distribution in the Skin of Bottlenosed Dolphins (Tursiops truncatus and Tursiops gilli). Jour. Morphol. 186(3):315-326.

Fat was rather evenly distributed in all strata of the epidermis. Unique extracellular fat droplets were observed among the collagen bundles of the dermis and unusual lipid particles were in some vessels of the dermal papillae. A unique extracellular transport of dermal lipids to the epidermis is postulated. Possible functions of epi- dermal lipids are discussed.

Stromberg, M. W. 1989. Dermal-epidermal Relationships in the Skin of the Bottlenosed Dolphin (Tursiops truncatus). Jour. Vet. Med., Ser. C: Anat. Histol. Embryol. 18:2-13.

Dolphin skin was studied by a variety of methods. The arrangement of dermal and corresponding epidermal structure is described. Distinct epidermal pegs were not observed. Results are compared with information in recent literature. Apparent con- flicts are discussed. The structure and scale of epidermal ridges are detailed.

Sweeney, J. C. 1974. Radiographic Atlas of the California Sea Lion. NUC TP 387, 16 pp.

A radiographic reference atlas with an evaluation of techniques for all of the stan- dard positions. Includes photographs and drawings of the normal radiographic anat- orny .

Tarpley, R. J., and S. H. Ridgway. 1991. Orbital Gland Structure and Secretions in the Atlantic Bottlenosed Dolphin (Tursiops truncatus). Jour. of Morphology 207:1-12.

The anatomy of the orbital gland that surrounds the dolphin's eye was elucidated in numerous drawings, photographs, and photomicrographs. The gland secretes the visco-elastic tear secretion of dolphins and some of the properties of this secretion are discussed.

Thomas, J. A., W. W. L. Au, C. W. Turl, and J. L. Pawloski. 1989. Sensory Systems of False Killer Whales. (Abstract) Abstracts of the Eighth Biennial Conference on the Biol- ogy of Marine Mammals, Soc. Mar. Mammalogy, Pacific Grove, CA., p. 67.

Studies on hearing and echolocation abilities are summarized. Results compared with bottlenosed dolphin and beluga studies.

Woods, D. L., S. H. Ridgway, and T. H. Bullock. 1986. Middle- and Long-latency Audi- tory Event-related Potentials in Dolphins. In: Dolphin Cognition and Behavior, pp. 6`1-77, eds. R. J. Schusterman, J. A. Thomas, and F. G. Wood, Lawrence Erlbaum Associates, Hillsdale, NJ.

In recordings of event-related potentials in response to a variety of auditory stimuli, certain responses suggested a more precise representation of auditory stimuli in

short-term memory in dolphins than in humans. Infrequent "deviant" stimuli pro- duced a component similar in some respects to the "decision-related" P300 wave in humans .

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