ALLEN — FOSSIL CETACEANS FROM FLORIDA 
149 
each intermaxillary. It is continued forward and inward beneath this bone and 
is probably the opening of a perforation of the maxillary quite obvious in most 
modern dolphins, but here covered by the expanded intermaxillary. The back- 
ward extension of the maxillary almost completely covers the outer part of the 
frontal, at least on the right-hand side, and thus heightens the appearance of 
fore-and-aft compression of the brain case. 
The intermaxillaries are brofld, thin and nearly plane. posteriorly, but quickly 
become narrower opposite the front of the blowholes, and then slightly expand, 
their surfaces sloping inward toward the triangular area in front of the nares, 
before continuing forward on to the beak. A very shallow groove runs from near 
the outermost part of this proximal expansion, forward and inward, becoming 
lost at the inner sloping margin of the triangular area. A similar groove is 
present in Schizodelphis. At this level commences a marked asymm^etry. The 
right intermaxillary suddenly narrows while the left broadens out for a short 
distance and becomes much thinner at its outer edge. Forward from this point 
both intermaxillaries become raised and thickened, extending as two parallel 
flat-topped ridges, closely appressed medially, to the broken extremity of the 
beak. From the flattened maxillaries they are sharply marked off by a deep longi- 
tudinal groove along the line of contact. The right intermaxillary is markedly 
the smaller and its delimiting groove the shallower. 
A fragment (2343 Fla. Geol. Surv.) from very near the tip of a rostrum, and 
apparently representing the same species, shows that the two intermaxillaries 
fuse medially toward their distal extremity. 
The base of the rostrum is peculiar in outline. Opposite the anterior tips of 
the pterygoids it becomes strongly compressed from side to side, with gently 
concave margins as seen from below; then it expands widely, reaching the greatest 
convexity opposite the base of the visible part of the vomer, beyond which it 
tapers forward to form the beak. The tooth rows begin just in advance of the 
widest expansion. There is thus a distinct neck formed at the base of the ros- 
trum succeeded by a convex expansion, very different from the gradual and even 
taper from the maxillary notches forward, seen in Schizodelphis. A somewhat 
similar outline is seen, however, in the newly discovered living genus, Lipotes 
(Miller, 1918). In ventral aspect, the entire palate in advance of the vomer is 
quite fiat with a shallow median V-shaped groove where the bevelled edges of 
the maxillaries meet. It thus differs markedly from Schizodelphis sulcatus, 
in which according to the figures of Dal Piaz (1903, p. 195) the maxillaries are 
strongly bevelled outward. At the base of the rostrum the pronounced asym- 
metry previously noted in the dorsal aspect is again evident. For while on the 
left-hand side of the beak the proximal part of the maxilla widely expands, carry- 
ing with it the tooth row, on the right-hand side the expansion is less marked, 
and the palatal surface is much more nearly in a vertical plane so that the tooth 
row is placed much higher on the cheek. The alveoli are also smaller and closer 
together on the right-hand side in this region. 
The vomer appears in advance of the palatals as a narrow lozenge-shaped 
slip about 100 mm. long by 8 wide in the broadest place. Fortunately enough 
remains of the posterior end of the vomer to fix the shape and position of the blow- 
holes. That of the right-hand side is much the smaller and opens well to the 
right of the median axis of the skull, while that of the left side is so much larger 
