6 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 76 



An enlarged and thickened wedge like lachrymal is inserted between 

 the supraorbital process of the frontal on the rear, and the horizontal 

 plate of the maxilla and the jugal on the front. It extends inward 

 beyond the internal wall of the infraorbital foramen, and apparently 

 was in contact with the pter\'goid. The position of the lachrymal 

 on the ventral face of the skull is more in agreement with that of 

 Kogia than any other cetacean known to the writer. In Squalodon 

 hariensis^ a splint-like process of the jugal extends backward from 

 the maxillary notch to the antero-inferior margin of the zygomatic 

 process of the squamosal. Anteriorly, the jugal in this fossil skull 

 occupies the same relative position, but its posterior extension is mis- 

 sing on both sides. 



The postorbital margins of the supraorbital processes of the frontal 

 are rounded and their postero-external angles are not perfect. A nar- 

 row groove between the patietal and the presphenoid gives passage to 

 the optic nerve from the interior of the braincase to the broad canal 

 which traverses the middle of the supraorbital process. The lower 

 portion of the narial passage is formed largely by the arching pala- 

 tines. As the pterygoid is missing the side of the passage is not 

 enclosed. 



Teeth. — All six of the teeth which are in place in the maxillae have 

 a well-marked cingulum. A distinctive feature is imparted to the 

 cingulum by the closely approximated minute cusps which arise from 

 it. Each of these teeth has two rather slender roots which are united 

 at the base by a slender isthmus. The crown of the sixth two-rooted 

 tooth is covered with rugose or striate enamel. The apex of the 

 crown of the left tooth is missing, but there remain six well-defined 

 cusps on the posterior, and four on the anterior cutting edge. The 

 apex of the corresponding tooth on the right side is damaged to an 

 even greater extent. Four cusps are present on the anterior cutting 

 edge and an equal number on the posterior. The crown of the fifth 

 two-rooted molar is higher than that of the sixth. There is a close 

 agreement between the left and the right teeth in general features. 

 Both have six well-defined cusps on the posterior cutting edge of 

 which the two basal ones are rather minute, and four less prominent 

 cusps on the anterior cutting edge. The fourth two-rooted teeth are 

 so imperfect and fractured that description is impossible, but the 

 sculpture of the enamel crown is the same as for the preceding. 



* Lortet, L., Note sur le Rhizoprion bariensis Jourdan, Archives du Museum 

 d'histoire naturelle de Lyon, vol. 4, pi. 25 bis, 1887. 



