342 Mr. R. I. Pocock on the 
noticeably shorter and less well developed than in Prion- 
ailurus. 
Genus IctarLuRus, Severtz. 
“ Ailurin,” Gervais, 1855, p. 86; for planiceps, Vig. & Horsf.*. 
Ictailurus, Severtzow, 1858, p. 387; type planiceps. 
Ailurogale, Fitzinger, 1869, p. 249; type planiceps. 
Allurina, Gill, 1871, p. 60; type planiceps. — 
. Plethelurus, Cope, 1882, p. 475; type planiceps. 
Only one species hitherto admitted. 
Distr. Malay Peninsula to Borneo. 
The skull in its elongated shape, the structure of the 
bulla, exceedingly compressed nasals, and deep postorbital 
constriction recalls in a measure that of Zibethailurus, but 
may be distinguished by several peculiarities both dental and 
cranialt. (1) The posterior border of the complete post- 
orbital bar is scarcely convex owing to the great width of 
the base of the malar portion. (2) The nasal branch of the 
premaxilla is slender and tolerably evenly attenuated. 
(3) The mesopterygoid fossa is very narrow, about twice 
as long as wide or even more. (4) The muzzle is broad and 
the palate nearly parallel-sided, the distance between the 
two anterior premolars being about equal to the distance 
between the inner cusps of the upper carnassials, and the 
suborbital edge of the palate has a conspicuous and narrow 
notch. (5) The occipital area is narrow, with a shallow 
lateral emargination, and the summit much more pointed 
than in Zibethailurus. 
In the mandible the coronoid is low, with a wide summit 
set well in advance of the backwardly projecting condyle and 
angular. The anterior end of each ramus, carrying the 
canine and incisor teeth, is strongly elevated, and there is a 
large postcauine gap when the jaws are closed. 
In the teeth the first upper premolar is unusually large 
* Although Gervais was the first author to give nominal distinction 
to this genus, the name he proposed is inadmissible, as a comparison 
between it and such terms as “ Chacal” and “ Renard ” of the same work 
will show. By Gray planiceps was associated with viverr?na under his 
genus Viverriceps. 
+ Whether the resemblances between these two cats are due to close 
affinity or are merely adaptive it seems to me to be impossible tosay. If 
the former, the two supply an interesting exception to the general rule in 
the Felide that thesmaller speciesof a genus have skulls of a more juvenile 
type than the larger, owing to the lesser development of constrictions 
and ridges associated with powerful masticatory muscles. I. planiceps, 
although considerably smaller than Z. viverrina, has, nevertheless, a skull 
indicating relatively greater masticatory power. 
