FOSSIL LEPORIDiE-PRAOTIlEKIUM. 



377 



ritlgc; enamol-boundnry emnrgiimtc on (he inner side. Number of molars in 

 max i Mary bone? four." — (Cope.) 



This genus, according to Professor Cope, difTers from Lrjnis mn\ Lagowys 

 in (he absence of an enamel band dividing the triturating surface of eacii 

 molar, though a trace of the dividing lamina is sometimes visil)le, but docs 

 not appear to ever form a transverse median crest. The normal number of 

 teeth is uncertain, but supposed to be only four on each side of the u|)per 

 jaw. Only one species has thus far been described, from remains found in 

 (he Port Kennedy bone-cave, Chester County, Pennsylvania, associated with 

 those of a great variety of extinct species, mingled with a few of species still 

 existing. The geims is known from the single species — 



PRAOTHERIUM PALATINUM Cope. 



PraoOurimm palaUnum CuPK, Proo. Aiuer. Phil. Hoc., xii, 1871, 04, Ug. 20. 



Tiiis species was described by Professor Cope from the palatal portion 

 of a sUull, containing four molar tetth on each side in position, found in I be 

 Port Kennedy bone-cave. It differs, says Professor Cope, from the Ameri- 

 can species of Ze/?Ma in its small size, and in having the molars deeply grooved 

 longitudinally on the inner instead of on tlie outer side. "In worn teeth, this 

 groove is continued into the grinding surface of the crown, without interrup- 

 tion from the inclosing enamel. The form of this surface is then an oval, 

 notched on the inner side, and rounded or slightly truncated on the outer 

 The palatine face is but partially preserved, and is considerably wider in pro- 

 portion to the diameter of the teeth than in Lopus sylvaticux." In Lepiis 

 calloth, however, there is a deep longitudinal groove on the outer side of 

 the tooth, and none on the inner; while, in L. callfornicus, there is quite a 

 distinct groove on both sides. The prominence, or even presence, of tiie 

 median transverse ridge varies with age in the living species, as Dr. Leidy 

 has shown it to do in specimens of Palceolagus haydeni. 



FOSSIL REMAINS OF EXISTING SPECIES. . ' 



In addition to the above described extinct species of Hares, the remains 

 of several of the existing species have been met with in different bone-cavea 

 and elsewhere, sometimes associated with the remains of a variety of other 

 extinct species of Mammalia. Dr. Leidy has recorded the occurrence of the 

 fossil remains of Lepus sylvatkus in the crevices of the lead-bearing rocks of 



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