1S92.] -I -J«J [Cope. 



emarginations on the inner border, ■which are wanting in the present 

 species.* 



The species is probably the oldest member of the genus Equus known 

 from North American beds. It is the only species wliich was contempo- 

 rary witli a Mastodon with the 31. amjustidens type of molars. The sim- 

 plicity of the enamel foldings is appropriate to this primitive period, as it 

 approximates to tlie condition seen in many of the three-toed horses and 

 the supposed one-toed HippiHum sjyectans Cope.f The size of the molars 

 is about that of the modern horse, B. caballus L. 



Observations. — The contemporaneity of this species of Equus with the 

 Mastodon with molars of the M. angustidens type has considerable sig- 

 nificance. The latter is characteristic of the Loup Fork horizon in North 

 America, in which the genus Equus does not occur. The Equus beds, so 

 named from the abundance of individuals of four species of Equus which 

 they contain, have never produced a specimen of Mastodon allied to M. 

 angustidens in ^on\\ KmG,nc?(,.X The fact that the Equus of tlie Staked 

 Plains is different from those of the Equus beds, adds to the indication 

 furnished by the Mastodon that these beds do not belong to the Equus 

 horizon ; but the presence of the genus Equus is equally conclusive that 

 they do not pertain to the Loup Fork. It is probable that the age of the 

 beds is intermediate. They thus offer an interesting field for further 

 research. 



Creccoides osbornii, Shufeldt, gen. et sp. nov. 



Char. gen. — Only a fragment of a left tarso- metatarsus represents this 

 new genus and species of bird. It evidently belonged to some wader of 

 about the proportions of a medium-sized heron, or to a form rather larger 

 than the Floridan crane-like rail Aramus. 



The specimen consists of about the superior moiety of the tarso meta- 

 tarsus, and, in so far as it goes, appears to be perfect, with the exception 

 of slight marginal abrasions of the summit of the bone and the almost 

 complete fracturing off of the hypotarsial process. Superiorly, the inler- 

 condyloid prominence or tubercle is rounded and not especially conspicu- 

 ous ; the inner condyloid depression is more extensive than the outer 

 one, and occupies a higher plane. In front the shaft is longitudinally 

 excavated only above, the excavation gradually but soon disappearing as 

 we pass down towards the distal extremity ; and at the midpart of its 



* The horse found in Florida by Mr. Wilcox, which Dr. Leidy identified as his Equua 

 fraternus (Transac. Wagner Free Inst. Science, Philadelphia, 1889, p. 16), must be referred 

 to a genus distinct from Ecjuus, on account of the absence of cups of the incisors, by (he 

 loss of the internal wall. This is seen in both unworn and worn specimens. In some 

 cases an internal cingulum remains to indicate its position. It appears to be a case of 

 degeneracy. I have named the genus Tomolabis. 



\ American Naturalist, 1887, p. 1072. 



X It is probable that the Dibelodon shepardii Leidy, which has molars of this type, 

 occurs in the Equus beds of the valley of Mexico. Cfr. Cope, Proceed. Amer. Philos. 

 Soc, 1884, May. 



