1878.] R. Lydekker — Aberrant Dentition of YiA\sT\^^v\s. 3 



tooth of the premolar series, and which, as we have seen, does not occur in 

 the normal dentition of the genus Felis ; on the left side of the figured 

 jaw this additional premolar is absent. 



The interest that attaches to the presence of this additional premolar 

 in our specimen, is that in an extinct genus of Fe/idce, the normal number 

 of the lower premolars was three in place of two, as in Felis. This exbinct 

 genus was named by M. Gervais ' Pseudcelurus,* and the one species 

 (P. quadridentatus) on which it was determined, was obtained from 

 the miocene formation of Sansan in France ; the species was previously 

 named by De Blainville in his " Osteographie," Felis quadridentatus and 

 F. tetraodon. Subsequently Professor Leidyf described a second species 

 of the genus, under the name of P. intrepidus, from the Pliocene of 

 Nebraska. Still later, I myself J described the lower jaw of a third 

 species, P. sivalensis, from the Siwaliks of this country. 



It is well known that the small number of the molar series which 

 exists in the living Felidce is a highly specialized character, which is not 

 found in the oldest carnivora, nor in many of those which are still living. 

 The existence of an additional lower premolar in the Miocene and Pliocene 

 genus Fseudcelurus shows that that genus is less specialized than Felis, and 

 indicates that the former was probably the line through which the latter 

 was described from some primitive carnivore in which the whole four of the 

 typical premolar series were developed. The occasional occurrence of the 

 ante-penultimate lower premolar in Felis must be regarded as an instance 

 of " reversion" towards the genus Fseudcdlurus. 



* "Zoologie et Paleontologie rran9aises", Vol. I, p. 127. 

 t "Extinct Mammalia of Dakota and Nebraska," p. 52. 

 t "Kecords of Geological Survey of India," Vol. X,, p. 83. 



