21(5 PROCEEDINGS OF THE ACADEMY OF [1889. 



latter, and there is no ridge running inwards from the paroccipital 

 process. There are also very large glenoid foramina. There is a 

 single large post-parietal foramen on each side of the sagittal crest. 

 The infra-orbital foramen is placed very close to the orbit, from which 

 it is separated only by a narrow bridge of bone ; it lies above pin. 3. 



The arrangement of foramina in Dinictis is thus seen to be very 

 much the same as that described by Cope in Archcelurus and others 

 of the NimravidcB (No. 2. p. 955), but no living carnivore presents 

 such an assemblage of characters in the basis cranii. These prim- 

 itive cats seem to show conclusively that the construction of the base 

 of the cranium has not the taxonomic value attributed to it by 

 Flower (No. 5) an opinion which Schlosser (No. 14, p. 233) has 

 reached on quite different grounds. The basis cranii of Dinictis is 

 perhaps on the whole more cynoid than anything else, though 

 ailuroid and even arctoid features occur. We shall return later to 

 a discussion of this cpiestion. 



The brain of Dinictis is unknown, but that of Hoplophoneus, a 

 nearly allied genus, has been described and figured by Bruce (No. 1, 

 p. 42, PI. vii, fig. 8). This is distinctly feline in character, though 

 as would naturally be expected, the convolutions are simpler aud less 

 winding; it bears obvious resemblance to the brain of Pseudozl urus 

 which Gervais has figured (No. 7, PI. 6, fig. 6) and which, as that 

 writer has pointed out, has certain affinities with the brain of Cryp- 

 toprocta and the viverrines. 



The Dentition. 



The dental formula of Dinictis is If CI Pm. f Ml, which, as 

 Leidy has observed, is the same as that of most mustelines, and also 

 occurs in JElurogale. 



•Upper Jaw. The incisors are in general cat-like and form a 

 straight, transversely directed row, separated by considerable dias- 

 temata from the canines. The external incisor is the largest of the 

 series and has a long, acute, conical and somewhat recurved crown, 

 except for its smaller size, very similar to that of Hoplophoneus. As 

 in that genus, there is no cingulum, such as occurs in the external 

 incisor of the cats. The median incisor is much smaller than the 

 outer one and has a simple pointed crown without cingulum. Only 

 the fang of the inner incisor is preserved, but this shows that the 

 tooth was still smaller and more compressed than the median one. 

 In Hoplophoneus the incisors are all much larger, all have similar 



