RHINOCEROS 



ApJielops fossiger 



THE occurrence of rhinoceros remains in Florida was noted by Dr. Leidy in 

 the " Proceedings of the Academy of Natural Sciences of Philadelphia" 

 for 1884, page 118, and in the Proceedings for 1885, pages 32 and 33, he 

 described a species which he named Rhinoceros proterus, basing it upon a last 

 upper molar. Subsequently a large number of teeth and bones were received 

 from Florida belonging to the same species. Unfortunately, no portion what- 

 ever of the skull was preserved, but a comparison of the teeth and bones with 

 the type of Aphclops fossiger (Cope), and with other Western material, shows 

 that at most Rhinoceros proterus can be considered only as a subspecies of 

 Aphelops fossiger, which may be distinguished as follows : similar to A. fossiger, 

 but with slightly smaller molars, having thinner crests ; a better development 

 of the cingulum on pm. ■§■ and ^, bones of the feet averaging a little heavier 

 and more rugose. Dental formula, i. \, c. f, pm. |-, m. f. The cutting surface 

 of the upper incisor, plate ix. fig. 4, ascribed to this subspecies by Dr. Leidy, 

 is elongate, rounded from front to back, and somewhat rounded on the side. 

 The lower incisor, plate xii. fig. i, is long, with a short, triangular, enamel- 

 covered point. The lower canine, plate xii. figs. 2, 3, and 4, is long and much 

 curved, with the convexity inward, the cutting portion wearing to a long, 

 smooth, chisel-like point. The young unworn canine shows a long, triangular, 

 sharp-cutting edge. 



An anticrochet is developed on all upper teeth back of the second pre- 

 molar. The inner angles of protoloph and metaloph are united by the back- 

 wardly directed crochet in pm. 2, 3, 4, the crochet becoming free on the first 

 molar. Professor Osborn, " Bull. Mus. Comp. Zool.," xx. part iii. pages 92 and 

 93, states that the anticrochet is absent in pm. 4 oi fossiger, but the specimens 

 in hand show that this may or may not be the case. The fourth premolar 

 of one specimen, plate ix. fig. 3, from Florida, bears a rudimentary crista, 

 while in one example oi fossiger the corresponding tooth has the crista well 

 developed and uniting with the metaloph to form a small fossette. In other 

 examples of both proterus and fossiger the crista is absent, so that the presence 



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