460 Annals of the Carnegie Museum. 



in regard to the former genus, but it has not been so easy, on account 

 of the lack of proper material for comparison, to remove all doubt in 

 regard to Palceomeryx. 



Some specimens recently received by the Carnegie Museum from 

 Europe, though not belonging to the type itself, and not from the 

 same locality as the type of Palceoineryx, enable me, without great 

 danger of serious error, to point out differences which exist between 

 PalcEomeryx and the American species, which have been referred to 

 that genus. It seems indeed that there is really no very intimate 

 relationship between the American and European forms, and it would 

 be an error to employ them for a close correlation of horizons. This 

 is only another example of the general rule that there are very few 

 mammalian genera common to the Eastern and Western Continents ; 

 and as more complete material accumulates and is more carefully 

 studied, the apparent number grows less. I therefore venture, in 

 order to prevent error and misconception, to suggest for the American 

 forms a new generic name. The possession of very complete material 

 permits a very satisfactory definition of the osteological characters of 

 the new genus. Some of the distinguishing features which separate it 

 from the European species, which have been referred to PalcEomeryx, 

 can be pointed out, and the differences which separate it from the 

 type oi PalcEome7yx can be stated with a large measure of certainty. 



The following are the characters which Cope gave for Blastoineryx 

 borealis : "The superior dental formula isl.o; Co; Pm.3 ; M.3. 

 The molars all have two pairs of crescents excepting the last premolar 

 where the posterior pair are rudimental. The external face of the 

 anterior crescent in all the molars presents a groove, which is bounded 

 posteriorly by a vertical ridge. The posterior crescent is directed a 

 little inward posteriorly on the true molars. The palate is much con- 

 tracted in front of the first molars. The horns stand above the pos- 

 terior parts of the orbits ; their section is triangular, the posterior 

 angle being rounded, and the external produced and acute, bounding 

 the orbits outwards and backwards. There is no trace of a burr. The 

 temporal fossae approach so as to be represented only by a rather wide 

 and low occipital crest. . . . This species was as large as the black- 

 tailed deer, Cariacus macrotis.''^ '" 



In Volume XVIII of the A^iierican Naturalist Cope observes that 



'° " Description of New Vertebrae from tlie Upper Tertiary of the West," Proc. 

 Amer. Philos. Soc, 1878, p. 223. 



