NO. 7 NEW TOOTHED CETACEAN FROM SOUTH CAROLINA 3 



present. At the end of the vomerine gutter and some distance above 

 it, there is a single large frontal fontanelle through which the nasal 

 branches of the ophthalmic (V) nerve probably passed. 



The premaxilla is narrowest near the third two-rooted tooth. Pos- 

 terior to this tooth, the premaxilla commences to expand horizontally 

 and attains its greatest width on the rostrum above the sixth two- 

 rooted tooth. At the level of the maxillary foramen the exposed 

 portion of the premaxilla is relatively narrow and from this point 

 posteriorly it is hidden for the most part by the overlying frontal 

 plate of the maxilla. Along the external boundary of the nasal 

 aperture the premaxilla has been elevated to form a thin edged crest 

 which commences in front of the maxillary foramen and follows the 

 internal border of the maxilla backward beyond the posterior margin 

 of the nasal. The anterior border of the nasal aperture is formed by 

 the upturned inner margins of the premaxillae. At its posterior ex- 

 tremity, the left premaxilla has a maximum breadth of 50 mm., 

 although it is largely hidden by the overlying maxilla. 



Though the braincase is absent, it is fairly certain that this skull 

 was characterized by a very narrow interorbital constriction. The 

 maxillae and premaxillae terminate above the anterior margins of the 

 temporal fossae. The premaxilla overspreads the frontal and a 

 portion of its supraorbital process, and in turn is overlapped by the 

 frontal plate of the maxilla though a wide triangular area is exposed 

 behind and above the postero-internal margin of the maxilla. The 

 maxilla increases in width from the extremity of the rostrum pos- 

 teriorly and attains its greatest width at the level of the nasals, but 

 because of the peculiar position of the lachrymal does not reach the 

 outer edge of the orbit. The internal margin of the maxilla is in 

 contact with the premaxilla for its entire length. 



The rostrum is depressed below the level of the orbits and in corre- 

 lation with this modification each maxilla is strongly excavated or 

 hollowed out between the maxillary notch and the fifth two-rooted 

 tooth. The broad base of the rostrum is formed mainly by the lateral 

 expansion of the maxillae. On the left side of the rostrum, the roots 

 of the fifth and sixth two-rooted teeth have pierced the dorsal face 

 of the maxilla and have been clinched. 



In contrast to all other known cetaceans, the lachrymal projects 

 backward along the outer margin of the supraorbital process of the 

 frontal as far as the postero-external angle of the maxilla and the 

 posterior margin of the eye. It agrees with certain forms, such as 

 Kogia, in that it curves downward in front of the supraorbital process 



