PALEONTOLOGY. 305 



tioii (231), a list of species is given, and the following new species and 

 genera described : 



Jmphicyon(1) r'ulpimtvi, ly. 255, no figure. 

 Plesiartomys sciuroides, p. 25G, uo figure 



Protoreodon parvus, gen. et sp. uov. _(? Agriochocrus, Marsh), (figure of the up- 

 per molar series). 

 LeptoiraguUts jjroavus, gen. et sp. nov., pp. 258, 259, no figure. 

 Hyrachyus ohliquidenH, p. 259. 



ProtUyracodon itiltrmcdium, gen. et sp. nov., p. 2G0, no figure. 

 Isectolophus aiinectens, gen. et sp. nov., p. 260, uo figure. 



Richard Owen (217) presents the evidence of the existence in Amer- 

 ica of mammals of the " Plastic Clay" period. 



Madame Pavlow (221) gives an account of comparative study of the 

 history of the Ungulates of America and Europe. 



Alexander Wiucbell (305) announces the discovery of bones of the 

 extinct Platygonus conqrrcssus in Ionia County, Michigan. The author 

 states that the bones are being arranged into four skeletons in the mu- 

 seum of the University of Michigan, and will be described and illus- 

 trated at some future time. 



E. D. Cope {4:6a) describes the following new genus and species from 

 the John Day Miocene of North America : 



Bothrolabis, Cope, (gen. nov.), p. 66, type B. rostratus, Cope; B. ros- 

 trains (sp. cov.), pp. 77-79. The author states (p. 63) that lithographic 

 plates of this species have been printed, but are unpublished. E. D. 

 Cope (54a, 43fl) discusses the mechanical origin of the dentition of 

 mammals. The author attempts (54a) to show why the AmhlypodUj 

 having at the start apparently the same mechanical condition with the 

 Carnivora, did not eventually produce the same result. He thinks that 

 the divergence of mammalian dentition into two types, the tritubercu- 

 lar and the quadritubercular, has been due to the adoption of different 

 food habits. "The tritubercular," he says, "is the primitive, and is 

 adapted for softer food, as flesh, so that the primitive Mammalia were 

 carnivorous, or nearly so. The mastication of hard food was impossi- 

 ble until the molars of the two series opposed each other, and this was 

 not accomplished until the quadritubercular or superior molar was pro- 

 duced." 



VEGETAL PALEONTOLOGY. 



Sir William Dawson (67) describes the Sporocarps of the Eriaa 

 Shale. The circular specimens, originally described as i^poranffites 

 Huronetm-'^, Dawson, are referred to the Fyotosalvinia Huronensis, Daw- 

 sou, page 138. The bifurcate form is described under the name Sporo- 

 carponfurcatum, page 139, and is illustrated in tig. 1, a, b, c, d. 



A remarkable specimen of Devonian Lepidodendron is briefly de- 

 scribed by C (56). INIention is made of the discovery of a large 



portion, 15 feet long, of the stem o\i n Lepidodendron prinnvvum, Rogers 

 (?), from the arenaceous Portage Shales of Naples, Ontario County, 

 H. Mis. 142 20 



