CATALOGUE OF THE CETACEA. 291 
laterally, than iu the specimens which I have seen. The teeth are more numerous (If), and the 
occipital condyles less rounded and prominent, but larger. It is quite possible that this skull may 
be that of a male. Those which I have examined were both of females. I consider the differences 
as at most no more than sexual, and probably only individual peculiarities ; and I have no doubt 
whatever of the identity of Captain Scammon's species with that described by Professor Gill. 
It is evidently the most abundant species on the coast of California, and varies considerably in 
size with age. It is very close to L. leucopleurus of the Atlantic. 
The following are the measurements of two crania, in inches and decimals : 
No. 1. No. 2. 
Length of skull in a straight line 16 .00 15 .50 
Internal length of brain cavity 5 .00 5 .00 
Length of beak before the maxillary notches 8 .00 8 .20 
Tip of beak to anterior margin of superior nares 10 .25 10 .00 
Tip of beak to posterior notch of palate 9 .75 ? 
Tip of beak to posterior tooth 7 .40 7 .75 
Height of skull at vertex 6 .75 5 .50 
Greatest breadth at zygomatic process of squamosals 8 .20 7 .50 
Breadth at supra -orbital ridge 7 .20 6 .30 
Breadth between maxillary notches 4 .GO 4 .00 
Breadth at middle of beak 3 .40 2 .80 
Width of condyles 4 .00 3 .25 
Closest approximation of condyles below the foramen magnum .12 .18 
Height of foramen magnum 1 .35 1 .30 
Width of foramen magnum 1 .35 1 .50 
Entire length of ramus of lower jaw 13 .00 12 .00? 
Tip to posterior edge of last tooth in lower jaw 7 .50 6 .75 
Length of symphysis 1 .30 1 .00 
Height of ramus at coronoid process 3 .00 2 .60 
Height of ramus at four inches froni tip of anterior end 1 .00 .95 
Width between outsides of articular surfaces 7 .25 6 .40 
Width between posterior teeth 3 .50 3 .50 
Length from tip of beak to superior transverse ridge behind frontals.. 13 .00 12 .00 
Length from tip of ramus to anterior notch of inferior dental foramen, 9 .00 7 .75 
Greatest width of premaxillaries 3 .75 ? 
Width of premaxillaries at middle of beak 2 .10 1 .60 
The surface of the beak in No. 1 is moderately and quite regularly arched from side to side, 
no grooves separating the maxillre and preinaxillse. The nasal triangle is nearly plaae, but elevated, 
and its surface rough ; behind, it gradually ascends ; before, it is gradually incurved, and is con- 
tinued as a narrow internal margin to the premaxillre, to the anterior fourth of the beak; its 
greatest width is less than half the width of the cranium. The mesethmoid groove is wide, and 
scarcely contracted in the middle. The sujjra - occipital projects forward, nearly or quite touching 
the nasals. The temporal fossse project far backward. 
The teeth are f-§ in number, elongated and boldly cm-ved, about four in an inch. The occiput 
is deeply impressed above the condyles. The mesethmoid plate is sharply pointed above, and 
divided into three lobes behind the narial openings, by perpendicular sutures, which are evident 
for an inch and a half vertically. The mesethmoid is evident for nearly an inch between the 
premaxillse in front of the superior nares. The pterygoids are obtusely keeled below, but not at 
the sides, and deeply roundly notched laterally. The palate is flat, constricted slightly at the 
palatines, and somewhat concave in the anterior half of the jaw. The periotics are wanting. A 
very peculiar feature of the cranium is the enormous development of the tentorium. The septum 
above it projects into the brain-case nearly two inches. From the base of this sei^tum, half an 
