G. I. Adams — Extinct Felidce. 147 



parable with that of the Hoplophoneus and Dinictis series. 

 The genus is represented in both JSTorth America and Europe 

 and it is probable from a jaw fragment described by Lydekker 

 as jElurogale sivalensis that the geographical range extended 

 to India. * 



Genus Machcerodus. 



I wish to add some notes from my observations of the type 

 skulls of M. meganteron and M. jxdmideus. Machcerodus 

 differs from ITqplqphoneits in having basal cusps on the pre- 

 molars and a small second anterior cusp on the superior sec- 

 torial. In regard to this last point I was in error in my 

 previous definition of the genus. The cusp being very small I 

 failed to recognize it in the illustrations, mistaking it for the 

 cingnlum. The alisphenoid canal is present just as in Hoj)lo- 

 phoneus and the post-tympanic and post-glenoid processes are 

 well separated. The close resemblance between the two genera 

 in other respects than those of dentition makes it very prob- 

 able that Hoplophoneus is the direct ancestor of Machcerodus. 



Genus Smilodon (Syn. Dinobastis Cope). 



There is a tendency among European palaeontologists to dis- 

 regard this genus, including it in Machcerodus. This is prob- 

 ably in part due to the fragmentary condition of European 

 specimens which often makes certain characteristics indetermi- 

 nate. The genus Smilodon differs from Machcerodus as regards 

 dental characters as follows. The second anterior cusp on the 

 superior sectorial, which is incipient in Machcerodus, is well 

 developed in Smilodon, and the basal cusps on the premolars 

 are much larger. The incisors have basal cusps, while in 

 Machcerodus there is only a suggestion of this element. There 

 are perhaps no new structural elements nor have any been lost, 

 but there are developmental differences. In the skull how- 

 ever there are decided structural differences, namely, the 

 absence of the alisphenoid canal and the coossification of the 

 post-glenoid and post-tympanic processes below the auditory 

 meatus. The teeth being the parts most often preserved, these 

 points are unfortunately indeterminate in some well known 

 specimens, but that should not be an excuse for overlooking 

 their value. Lydekker has figured the posterior portion of a 

 skull of M. sivalensis-\ Falc. and Caut., showing the coossifi- 



*Pal. Indica, Series X, vol. ii, p. 317. 



f The indistinct figure of the superior sectorial of this species, so often repeated 

 along with the statement that it possesses an internal cusp, has caused some con- 

 fusion. Bose has previously stated that it has none. An examination of the 

 specimen shows that there is an internal buttress as is commonly found in the 

 genus, but no cusp. 



