60 Annals of the Carnegie Museum. 



ovei teaches us that in the apes, as in man, we often meet with very 

 marked variation in the mattei of form, when we come to compare the 

 skulls of individuals belonging to the same species, and that there are 

 very wide variations to be noted among the skulls of the various 

 genera of apes, as in the vaiious races of men. In long seiies of the 

 skulls of apes we would also probably find more or less constant dif- 

 feiences distinguishing the skulls of the two sexes. 



In its general appearance, the skull in Lasiopyga griseoviridis has a 

 far more brutish aspect than in Lasiopyga callitrichus; this is well 

 shown in figures 1-8 of the plates, and the reason is very evident; for, 

 in the first-named ape, the supra-orbital ridges are very prominent 

 with rounded borders, and, as they lie entirely in the horizontal plane, 

 they merge indistinguishably with each other in the middle line, lend- 

 ing to the entire skull a very forbidding aspect. This is further 

 enhanced by the prominence of the remainder of the orbital peripher- 

 ies, and the extreme flatness of the vault of the cranium, as compared 

 with the more human-like rounded dome of the calvarium in L. 

 callitrichus. Furthermore all the muscular lines, depressions, pro- 

 cesses, and other osseous characters in L. griseoviridis are more pro- 

 nounced, more prominent, sharper, and more distinct than in L. 

 callitrichus; to which must be added the feature of the upper canine 

 teeth, which in L. griseoviridis are much longer in proportion, more 

 curved, and in front exhibit deep grooves running their entire length, 

 these grooves being more internal and by no means prominent in the 

 upper canines of the other ape. In fact the skull of L. callitrichtis 

 has all these characters very much reduced in prominence, and the 

 existing differences are very much as we find them upon comparing 

 the skull of a highbred, intelligent Caucasian with the skull of a low, 

 savage Ethiopian, such as I have elsewhere figured in my works upon 

 that race. These characters of the crania are also evident when we 

 come to compare the mandibles of these two apes; for the angle at 

 the posterior termination of the symphysis is far more rounded in 

 L. callitrichus than it is in L. griseoviridis, and again there are the 

 difTerences in the canine teeth, though these are not grooved as they 

 are in the upper jaw. For the rest, the dental armature is well known 

 and has been frequently described, as it likewise has been for CalUthrix 

 jacchns, rendering it needless to repeat here. This marmoset also has a 

 skull which is entirely lacking in all those characters which lend such 

 a savage and brutish aspect to the skull of the Green Guenon as just 



