94 BULLETIN: MUSEUM OF COMPARATIVE ZOOLOGY. 



limitation is a necessary consequence of the fact that our only knowledge of the 

 form is derived from a fragmentary portion of the rostrum, shown of the natural 

 size in Plate 4, Fig. 1. The original belongs to the J. D. Whitney Collection, 

 presented to the Museum in 1895. It would be superfluous to add anything to 

 Leidy's excellent description (Proc. Acad. Nat. Sci. Phil., 1868, p. 197), which 

 is reproduced in the following paragraph : — 



" Delphinus occiduus. — An extinct species is indicated by a fossil derived from 

 the upper miocene formation of Half -moon Bay, California, submitted to my ex- 

 amination by Prof. J. D. Whitney. The specimen consists of an intermediate 

 portion of the upper jaw, devoid of teeth, and encrusted with selenite. It measures 

 along the more perfect lateral border 5 inches, and in this extent is occupied with 

 19 closely set, circular alveoli, rather over two lines in diameter. At the back of 

 the fragment the jaw has measured a little more than 2 inches wide. From this 

 position it gradually tapers for half its length, and then proceeds with parallel 

 sides to the fore end, where it is 10£ lines wide. The palate behind is nearly plane 

 or slightly convex ; at its fore part it presents a deep median groove, closed by the 

 apposition of the maxillaries, and this groove is separated only by a narrow ridge 

 from the alveoli. The sides of the maxillaries are slightly concave longitudinally, 

 convex transversely. The intermaxillaries are broken away, leaving a wide, angu- 

 lar gutter between the remains of the maxillaries." 





