SKULL OF LUTRA. CANADENSIS. 303 



with a general ovoidal contour. The occipital crest is moder- 

 ately developed ; the line of contour it represents is emargiuate 

 on the middle line, then strongly convex on each side, thence 

 about straight to its termination at the mastoids. There is 

 rarely, if ever, even in the oldest skulls, a decided sagittal crest, 

 the median line being in facti rather a groove, at least behind ; 

 in front, however, there is a slight raised line. In young 

 animals, there are several parallel grooves and striie along the 

 median line. 



The occipital face of the skull is in general flat, with various 

 muscular irregularities, curviug around laterally to the mastoid 

 region. It is bounded above by the occipital crest, the general 

 contour of which, in this view, resembles the dorsal profile of 

 a military chapeau. The condyles are large, and the region 

 around the foramen magnum is prominent; it descends far below 

 the level of the slight obtuse paroccipitals, the ai)ices of which 

 fall on the level of a line drawn from the mastoid to the middle 

 of the foramen magnum. The articular surfaces of the con- 

 dyles are obliquely oval, with no outward prolongation, but, on 

 the contrary, an extension toward the median line till they 

 nearly meet each other beneath the foramen magnum. This 

 aperture, in general outline, is transversely elliptical, broader 

 than deep, with a strong emargiuation posteriorly. 



The zygomatic width of the skull, best viewed from below, 

 is seen to be not much less than three-fourths the total length 

 (2.90 X 4.20 inches for example) ; the intermastoid width is 

 about three-fifths the length. The zygomata are widest apart 

 behind, thence approximately moderately in a nearly straight 

 line. The alveolar borders of the palate are about parallel 

 anteriorly, and, though divergent behind, this is mostly due to 

 the size of the back teeth themselves, the general palatal mar- 

 gins inside the teeth being parallel. The palate extends far 

 back of the last molars (not so far, however, as in Taxidea), 

 ending about half-way to the ends of the pterygoids. The 

 incisive foramina, very short and broadly oval, are directly be- 

 tween the canines. The emargiuation between the pterygoids 

 is broad, and ends with a rounded outline (with a median process 

 or median emargiuation indifferently); these bones are laminar, 

 smooth inside, thickened with various muscular ridges outside, 

 end in long hamular processes. The glenoid fossa is deep; it 

 develops a broad overlapping shelf at its inner back corner, 

 and a similar but slighter one at the outer anterior corner, 



