go NATURAL SCIENCE. apr.l. 



position of the posterior tine, which clearly represents that of the 

 latter. Professor Nehring has some doubts whether this deer ought 

 not to be regarded as a distinct species. 



An important contribution to the ancestral history of the Horse 

 is afforded by Professor \V. B. Scott's memoir on MesoJiippus and 

 Leptomeryx in the December number of the Journal of Morphology 

 (vol. v., pp. 301-406, pis. xxii., xxiii.). MesoJiippus, from the White 

 River Miocene of the United States, was an animal about the size of 

 a Newfoundland dog, and closely allied to Anchitherinm of the Miocene 

 of Europe. According to Professor Scott it was distinguished from 

 the latter by the absence of any rudiment of the infolding of the 

 crowns of the upper incisor teeth (comparable to that occurring in 

 those of the horse), and by certain details in the structure of the 

 other teeth and the limbs. Mesohippus is considered to have occupied 

 a position near the middle of the ancestral " phylum" of the horse, 

 while it is suggested that Anchithermm may have been a side branch. 



The other animal described in the same memoir is Leptomeryx, 

 which Dr. Scott regards as closely allied to the modern chevrotains, 

 but showing certain resemblances in the form of the incisors and the 

 auditory bullae of the skull to the true Ruminants or Pecora. The 

 latter features are, however, considered to have been independently 

 acquired. 



In the last number of the American Journal of Science (vol. xliii., 

 pp. 249-262, pis. v.-xi.) Professor O. C. Marsh gives a further instal- 

 ment of his researches on the fossil mammals of the Laramie 

 Cretaceous beds of the United States. It is considered that the 

 fauna indicates a marked break between the Laramie Cretaceous and 

 the Puerco, or Lower Wahsatch, Eocene beds. The mammalian 

 remains obtained from the former are now very numerous, although, 

 unfortunately, very fragmentary, consisting mostly of detached teeth. 

 Professor Marsh describes a number of these specimens, of which 

 many are regarded as indicating new species or genera. We consider 

 this reckless multiplication of names much to be deplored, as there is 

 little doubt that far too many species and genera have already been 

 made upon the evidence of specimens from these deposits. That the 

 number of so-called species and genera will eventually have to be 

 reduced materially, Professor Marsh himself seems to have a 

 suspicion, when he attempts to warn off criticism by saying that, in 

 comparison with describing species on the evidence of imperfect 

 specimens, " it is a matter of much less importance if such discoveries 

 should prove that two or more specimens, described as distinct, really 

 pertained to one animal." 



A large proportion of the remains described belong to the group 

 generally known as Multituberculata (Allotheria of Professor Marsh) ; 



