154 



MEASUREMENTS AND GLOSSARY OF MARINE MAMMAL TERMS 



Baculum - a slender bone within the penis of some mammals. It lies well 

 beneath the skin, between the penile opening and the anus, and can 

 be used in the identification of sea otters, seals, sea lions, and 

 walrus (Plate 38a and b) . 



Baleen - the horny fringed plates hanging from the roof of the mouth of 

 some cetaceans (Fig. 27). 



Beak - the forward portion of the head of some cetaceans in front of the 

 forehead. It is constricted relative to the forehead (Fig. 28; 

 see snout and rostrum). 



Blowhole slit - the external opening of the breathing apparatus when 

 the opening is closed (Figs. 27,28). 



Canine - (canine tooth) the large teeth just behind the incisors. There 

 is one such tooth in each side of upper and lower jaws (Fig. 29). 



Cetacean - a member of the order Cetacea: a whale, dolphin, or porpoise. 



Cusps - the bumps or projections on the biting surface of teeth 

 (see "molar" in Fig. 29). 



Dorsal - the upper surface (Fig. 28). 



Flukes - the horizontally broadened portion of a cetacean's tail (Fig. 28) 



Guard Hairs - longest, stiffest and most apparent hairs in a mammal's 



coat. This contrasts with the short, velvety fur beneath the guard 

 hairs. 



Longitudinal - a line along the anterior-posterior axis; in marine 

 mammals, along the length of the body. 



Palate - the roof of the mouth (Figs. 34, 36). 



Pelage - fur. 



Pinna - the external ear. 



Pinniped - a member of the order Pinnipedia: a seal, sea lion, or walrus; 

 literally, "feather- foot". 



Plate - a single sheet of baleen (Fig. 27). 



Postcanine - one of those teeth posterior to the canines; the premolars 

 and molars (Fig. 29). 



