Shufeldt: Osteology of Lasiopyga and Callitiirix. 65 



The external pterygoidal plates of the sphenoid are very prominent, 

 quadiilateral in outline, and turned outwardly; the internal plates 

 are not more than one-fifth the size of these; but each supports a 

 distinct hamular process. Either pteryp,oidal fossa is deep and has 

 from two to twenty minute foramina at its base. The basilar process 

 of the occipital is broad and elongated, but does not extend as far 

 forward as the petrous portion of the temporal upon either side. 

 The carotid foramen is very distinct and circular, and I find no 

 posterior condyloid foramen present. The foramen ovale is of fair 

 size, and located as in the cranium of man. Other small cranial 

 foiamina and openings are also present. The vomer is bifurcated 

 posteriorly, the bifurcations receiving the sharp palatal process of the 

 sphenoid. This is a striking feature of the base of both of these skulls 

 ( Cf. Plate XV, figs. 7 and 8). 



In L. callitrichus the occipital surface is very smooth and lacking in 

 depressions; while in L. griseoviridis it is decidedly roughened for 

 muscular attachment two-thirds of the way up to the lamboidal suture, 

 and in this area presents mesially a raised, longitudinal crest, the 

 internal occipital crest, which merges into the general surface of the 

 bone at its extremities. 



The foramen magnum is subcircular in outline, and rather large 

 for the size of the animal in either species. The condyles are elongated 

 and narrow, and occupy half the periphery of the anterior margin of 

 the foramen. Mesially they are separated by a very shallow notch. 

 The occiput makes an angle with the basis cranii of about 45°, that 

 of the plane of the foramen magnum being considerably less. An- 

 other well-marked character, piesent on either side in both species, is 

 the Glaserian fissure, occupying a position similar to w^hat we find 

 in anthropotomy. 



Lasiopyga has a strong and powerful mandible, with its two parts 

 in the adult thoroughly and indistinguishably fused at the symphysis; 

 Callithrix has the ramal portion very thin, broad and quadrilateial 

 in outline; while the body is not as strong in proportion as it is in some 

 of the higher apes. The infradental and mental foramina are minute 

 and single. Internally at the symphysis neither tubercles nor fossa 

 are found in Callithrix; while in Lasiopyga a deep fossa is always 

 present where the "genial tubercles" are found in man, and at the 

 base of this fossa we find a circular foramen piercing the bone in the 

 median line, to appear externally at the center of the bone, half-way 



