390 TRUE— ON THE CLASSIFICATION OF THE CETACEA. [April 24 



ters recalls Stcnodelphis rather than Inia, although the former 

 has a dorsal fin. 



Professor Abel's chief reason for rejecting Dclphinaptcrits and 

 Monodon from the Delphinidse appears to be that the cervical ver- 

 tebrae are separate. He says that on this account they cannot be 

 derived from Delphinidse." This seems to me illogical, for it must 

 be true that the existing Delphinidse with extremely thin, more or 

 less rudimentary, and anchylosed cervicals were derived from forms 

 with well-developed, separate cervicals. Hence, one might expect 

 to find some forms still existing in which the cervicals are distinct. 

 I do not think that on that account alone they should be rejected 

 from among the Delphinidse. 



In this connection, the genus Lophocctus from the Miocene of 

 Maryland is of interest. This is represented by a skull and cervical 

 vertebrae. The skull, which is long-beaked, is delphinoid in general 

 appearance, especially in the prenarial region, but the temporal 

 fossae are large and the supraoccipital narrow, and shaped somewhat 

 as in Inia. The teeth are lacking, but appear to have had simple 

 cylindrical roots. The cervical vertebrae are separate. They are, 

 however, imbedded in the matrix, so that little can be determined 

 regarding their characters. 



This genus has been associated with Inia in the Platanistidae 

 by Cope;^- and Dr. C. R. Eastman, who has recently given a new 

 description of it,^^ also regards it as allied to Inia, while Brandt 

 and Abel have considered it closely allied to Delphinapterus. I am 

 myself inclined to the latter view, although conceding that the shape 

 of the supraoccipital is inioid. If this be accepted, we have in 

 Lophocetus a Miocene delphinoid form with separate cervicals. 



On account of the combination of characters presented by Steno- 

 delphis, Delphinapterus, Monodon and Lophocetus, three courses 

 are possible as regards their classification. They may be included 

 in the family Iniidae, or made the basis of a separate family Steno- 

 delphidse, or included in the family Delphinidae. The latter course 

 seems to me best at present, 



"Mew. Mus. Roy. Hist. Nat. Belgique, 3, 1905. 

 " Anier. Nat., 1890, pp. 606 and 615. 

 ^^ Bull. Mus. Comp. ZooL, 51, 1907, p. 79. 



