480 The American Naturalist. [June, 



Pelecypoda, 1 of Scaphopoda, 18 of Gastropoda, 18 of Cephalopoda 

 (15 Ammonoids, 3 Belemnites). The other 7 species include 5 Brach- 

 iopoda and 2 Echinoderraata. 



The brief introduction comprises a geological description of the beds, 

 with a discussion of their age, and of their relations to various other 

 formations characterized by a similar fauna. 



The new, species are figured on twenty page plates. 



Notes on the Fossil Mammalia of Europe, IV.— On the 

 Pseudoequines of the Upper Eocene of France.— Under the 

 term Pseudoequines may be included the various species of the genus 

 Paloplotherium, which occur in the Upper Eocene and Oligocene of 

 Europe. This phylum parallels in a remarkable manner many of the 

 characters which are typical of the true horses, but these characters, 

 strange to say, are much earlier differentiated than in the real equine 

 phylum. 



Kowalevsky* in his great work on " Anthracotherium " clearly rec- 

 ognizes in his phylogenetic table of the Ungulates, that Paloplotherium 

 is not in the direct line of the horses. Schlosser is also of the same 

 opinion as Kowalevsky in regard to the relations of Paloptotherium to 

 the horses. Professor Gaudry 3 as late as 1888 placed all the species of 

 Paloplotherium in the direct line leading to Equus. 



The earliest known species referred to Paloplotherium is the P. codi- 

 ci<Nsr Gaudry ; this form is from the Calcaire Grossier or Middle 

 Eocene. ^ In P. codiciense there are four upper and lower premolars, 

 whereas in the more typical species of Paloplotherium from later de- 

 posits there are only three premolars. Moreover, in the P. codiciense 

 all the upper premolars are simpler in structure than the true molars. 

 The hist upper premolar in this species is tritubucular in structure, and 

 there are two well defined crests running outwards from the deutero- 

 cone, in other words this tooth is well adapted for further evolution 

 into the molariform last premolar of the typical Paloplotheroids. In 

 the true molars of P. codiciense the ectoloph has nearly the same form 

 as that of the Palaeotheridse in general, the metaloph or posterior crest, 

 however, is less oblique in position than in the later species of Palo- 

 phtherium and PalmAherium. The type specimen of Paloplotherium 

 eoditietue consists of a facial portion of a skull with the teeth well pre- 

 served. This species is much larger than P. minus and corresponds 

 more nearly in size with P. annecfen*. 



, p. 152. 



