PALEONTOLOGY. 305 



tion (231), 11 list of species is given, and the following new species and 

 genera described : 



Ampliicyon(l) vuJpinu7n,Y). 255, no fignro. 

 Pletiiartomys sciuroidcs, p. 250, no figure 



Protoreodon parvus, goii. et sp. nov. (? AfjriocJtocrus, Marsh), (figure of the up- 

 per molar scries). 

 Leptotragulus proavus, gen. et sp. uov., pp. 258, 250, no figure. 

 Hi/rachijus obJiquidenn, p. 259. 



Prothyracodo)! itiitrmcdiiim, gen. et sp. uov., p. 2C0, uo figure. 

 Iscctohphits ainiectens, gen. et sp. nov., p. 260, no figure. 



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

 ica of inaminals of tbe " Plastic Clay " period. 



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

 history of the Ungulates of America and Europe. 



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

 extinct Platrjgonns comprcssus in Ionia County, Michigan. The author 

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

 seum of the University of Michigan, and w ill be described and illus- 

 trated at some future time. 



E. D. Cope (4Grt) describes the following new genus and species from 

 tlie John Day Miocene of Korth America : 



Bothrolabin, Cope, (gen. nov.), p. G6, type B. rostralm, Cope; B.ros- 

 iratus (sp. rov.), pp. 77-79. The author states (p. G3) that lithographic 

 l)lates of this species have been printed, but are unpublished. E. D. 

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

 mammals. The author attempts (54rt) to show why the Ainhlypoda, 

 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 dift'erent 

 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 PALAEONTOLOGY. 



Sir William Dawson (07) describes the Sporocarps of the Erian 

 Shale. The circular specimens, originally described as t^porarKjites 

 Iluroiiensifi, Dawson, are referred to tha Frotosalriiiia Huroyiensis, Daw- 

 son, i)age 138. The bifurcate form is described under the name >Sporo- 

 carjwn furcatuni, page 130, and is illustrated in lig. 1, a, b, c, d. 



A remarkable spocninen of Devonian Lepidodendron ' \^ briefly de- 

 scribed by C (50). IMcntion is made of the discovery of a large 



portion, 15 feet long, of the stem of a Lepidodendron primcvvum, Rogers 

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

 U, Mis. 142 20 



