66 Annals of the Carnegie Museum. 



between the alveolar process and the inferior border. The infradental 

 and mental foramina are generally single in Lasiopyga as in Callithrix; 

 but there are two foramina on either side in the jaw of L. callitrichtis 

 before me. In this last species the coronoid process is higher than the 

 condyle on either side, and the sigmoid notch shorter and deeper than 

 it is in L. griseoviridis. In Lasiopyga the notch is always long and 

 shallow (Plate XIII, figs. 3, 4, and Plate XVI, fig. 10). The areas 

 for the attachment of muscles, especially for the buccinator and internal 

 pterygoid, are more or less roughened. The angle of the ramus is 

 always rounded, and instead of their being a ' mental process' to repre- 

 sent a chin, as in man, the mandible in all. these apes slopes from the 

 teeth downwards and backwards as shown in Plate XIII, figs. 3, 4, 

 and Plate XVI, fig. 10. 



I find no good figures of the skeleton of Lasiopyga in the literature 

 accessible to me. The one which has so long done duty in Huxley's 

 "The Anatomy of Vertebrate Animals," is incorrectly drawn in nearly 

 all particulars; it has no canine teeth, the zygoma is not that of an ape, 

 in short it is not a skeleton of Lasiopyga. 



Almost all of the laryngeal box in these apes ossifie? in the adult, 

 certainly in Callithrix, while the trachial rings seem to be only formed 

 in caitilage, or, at the most, in elementary bone. De Blainville, Owen, 

 Mivart, and other comparative anatomists have all referred to the 

 enormously developed body of the hyoid in Mycetes seniculus; while 

 Flower and others have described the hyoid in other New and Old 

 World apes, as in Cynocephaliis porcariiis and Lagothrix hiimholdtii, 

 cerato-hyals and epi-hyals being found in the last-named species. 

 Flower further stated in his Osteology of the Mammalia that "In very 

 few of the Old World monkej's is there any ossification in the anterior 

 hyoid arch; but in some Cercopithecl a short, bony, cerato-hyal is 

 found. This occurs also in the American Monkeys, with occasionally 

 the addition of a second piece (epi-hyal)." It would appear that the 

 presence of an ossified stylo-hyal in any of the apes is of extremely 

 rare occurrence, though sometimes a very small tN'mpano-hyal 

 became ossified. 



In the skeleton of Lasiopyga griseoviridis (C. M., No. Mf-"-^) the 

 basi-hyal is large and completely ossified. It has a length of 1.3 cm., 

 and a width above of 1.2 cm. It is broad above, and narrow below, 

 where it bifurcates, the processes thus formed being separated by a 

 rounded notch. Posteriorly it is deeply concave, especially above, 



