164 



KEY TO MARINE MAMMALS (Cont.) 



7 A longitudinal ridge of bone (sagittal crest) on top of skull, very 

 prominent in older animals, but in individuals less than 185 cm from 

 tip of tail to snout (+_ 5 years old) the crest is no more than 5 mm 

 high and may not be felt through the muscle and fur (Figs. 30, 33); 

 color dark brown to light tan; no gap between upper molar (last 

 tooth) and premolars (Fig. 33); if skull is exposed, postorbital 

 process triangular (Fig. 34); distal end of baculum has two knobs 

 (Plate 38); baculum length to 137 mm; animal never more than 2.4 m 



total length. CALIFORNIA SEA LION 



7' No noticeable ridge of bone on top of skull (Fig. 33); adult color 

 brown to yellowish, occasionally almost white; gap between upper 

 molar (innermost tooth) and premolars as wide or much wider than 

 a premolar (Fig. 33); in exposed skull, postorbital process square 

 (Fig. 34) distal end of baculum flared into a more or less disc 

 (Plate 38); baculum length to 192 mm; animal can be longer than 

 2.4 m total length. NORTHERN SEA LION 



8 No gap between upper molar (innermost tooth) and premolars (Fig. 33); 

 color usually dark brown; in exposed skull, postorbital process 

 triangular (Fig. 34); animal never more than 1.9 m total length. 



CALIFORNIA SEA LION 



8' Gap between upper molar (innermost tooth) and premolars as wide or 

 much wider than a premolar (Fig. 33); color brown to yellowish; in 

 exposed skull, postorbital process square (Fig. 34); animal can be 

 longer than 1.9 m total length. NORTHERN SEA LION 



9 Muzzle narrow and pointed (as in a collie dog; Fig. 35); fur on fore- 

 limb extends onto upper surface of flipper; six teeth behind each of 

 the long, pointed canine teeth; in exposed skull (refer to Figs. 



29, 30), interorbital area short, usually less than 20 percent of 

 condylobasal length; tympanic bullae convex; nasal bones long and 

 slender; combined anterior width about 40-50 percent of length; sides 

 of palate parallel between first and third postcanine . 



GUADALUPE FUR SEAL 



9' Muzzle not conspicuously long and pointed (Fig. 35); fur on forelimb 

 stops in abrupt line at wrist; five postcanine teeth (rarely six); 



in exposed skull, interorbital area longer, usually greater than 20 

 percent of condylobasal length; tympanic bullae concave; nasals 

 short and wide, combined anterior width about 80-90 percent of 

 length; sides of palate not parallel between first and third post- 

 canine. NORTHERN FUR SEAL 



