M^ 



INSTITUTF, OF SCIKNCE. PHILADELPHIA. 2T 



arrangement of the enamel on the worn triturating surface is sufficiently 

 like that of the Archer tooth, as represented in the subjoined woodcut, 



to render it probable thej' might belong to the 

 same species. However, in another specimen from 

 Ashley River, as seen in fig. 32 of the work just 

 indicated, the inner column of the tooth is retained 

 and is observed to be cylindrical or regularly cir- 

 -^ cular in transverse section, whereas in the Archer 



tooth it is compressed cj'lindrical or in section 



Hippotherium ingennum. ,,■ ^- 1 f 1- 1 ^a- -4. u ■ c j 



elliptical, from which dinerence it may be inferred 

 that the latter pertains to another species from the former. 



Later, an additional specimen, received from Archer, is a last upper 

 molar referable to H. ingcmmm. It is scarcely worn and so closely accords 

 in size and other respects with the tooth above described as even to render 

 it probable it may have belonged to the same individual. 



In relation with the above, it is a fit opportunity to describe a few re- 

 mains of another species of Hippothcriinii, previously noticed in the Pro- 

 ceedings of the Academy of Natural Sciences of Philadelphia, 1882, p. 290, 

 under the name of Hippotlieriuni montezuma. The specimens, submitted to 

 the examination of the author by the Secretary of the Smithsonian Institu- 

 tion, were presented to it by Mr. Ellis Clarke, Jr., who obtained them from 

 near Lacualtipan, Hidalgo, Mexico. They consi.st of a couple of bone 

 fragments and three molar teeth, and are stated to have been found in a bed 

 of clay beneath one of shell limestone and above a four-foot bed of coal. 

 The strata are probably of late tertiary age. 



The fossils indicate an animal smaller than Hippotlicruun plicatile and 

 about the size of H. ingennum. Of the bone fragments, one is the upper 

 extremity of a metatarsal, repre.sented in figs. 5, 6, plate V. It exhibits at 

 the sides well-marked impressions of the lateral, smaller metatarsals. The 

 articular end measures 27 mm. transversely and 23 mm. fore and aft. The 

 other fragment is the extreme, proximal articular end of a pastern repre- 

 sented in fig. 7, of the same plate. It is considerably wider transversely 

 than the corresponding part in H. ingcmunn and of less width fore and aft, 

 measuring 29 mm. in the former and 16.5 mm. in the latter direction. It 

 would appear to indicate a broader, less thick and perhaps shorter foot than 

 in H. iiigenuuni. 



Of the teeth, two are lower molars, apparently from different individuals. 

 One, a fourth or fifth of the series, is little worn, and it has lost its exterior 

 cementum. It is about 2 inches long and at the triturating surface is 

 20 mm. fore and aft, and 9 mm. transversely. The other, probably the third 

 molar, is about half worn, but is broken away below and yet retains its 

 exterior cementum. It measures 19 mm. fore and aft and 1 1 mm. trans- 

 versely. 



