in existing Species of Felide. 331 
of isabellina in the particulars just mentioned—that is to 
say, the partition does not advance so far internally in front, 
so that the anterior portion of the inner chamber is much 
broader. On the other hand, the posterior portion of this 
chamber is less capacious. One skull of F. rufa—or a 
closely related form—agrees substantially in the structure 
of the bulla with those of F. canadensis. 
The bull of several examples of F. caracal agree closely 
with those of F’. rufa and canadensis, except that the posterior 
chamber is relatively more capacious aud the outer chamber 
slightly less so. 
Felis geoffroyi. (La Plata.) 
A. Right bulla, from below, with inner chamber laid open. 
B. The same, from the inner side. 
C. The same, from the outer side. 
p., partition; x., periotic; p.’, line of origin of partition. 
Resembling the lynxes in varying degree, according to the 
species, are the cats belonging to the genus Felis in the 
strict sense of the word—namely, Ff. ocreata, sylvestris, 
ornata, chaus, nigripes, and their allies (fig. 4). In this group 
the partition is relatively as high and as large in nigripes as 
it is in lynxes and is considerably larger than in ocreata, 
ornata, and sylvestris. In chaus it is still smaller. But in 
all cases the partition is very noticeably larger and rises 
higher above the crest of the tympanic annulus than in 
pardalis, nebulosa, planiceps, marmorata, and others which 
resemble Panthera pardus and onca in having a low partition 
