Mr. Bridges during his residence at David, in the same country, procured a skeleton of a Chrysothrix, perhaps C. sciurea.
It thus appears evident that species of Monkeys of the genera Mycetes, Ateles, Cebus, Chrysothrix and Hapale are found northwards of the isthmus of Panama, and that the Ateles extends its range up to the 23° N.L.
This is all the information I have been enabled to collect concerning the Quadrumana of the trans-panamanic province. I sincerely trust that Mr. Salvin, who is now returning to Central America in company with Mr. Godwin, for the purpose of making collections in Natural History, will endeavour to render our knowledge of this subject more perfect. The ignorance which prevails concerning it is mainly attributable to the carelessness and negligence Naturalists have hitherto shown as to the record of precise localities.
Having had an opportunity of dissecting the muscles of an Orang Utang, and of comparing them with those of the Magot (Inuus Rhesus) and of the Cebus Capuchinus, I have put together the following remarks on their myology, in the hope of drawing general attention to some points which have usually been overlooked.
I shall endeavour to point out the variations existing in the different species of the Quadrumana, as illustrated by the above-mentioned species, and to show how much closer is the connexion between the myological structure of the Platyrrhine prehensile-tailed Cebus and the Magot, than that existing between the latter animal and the Orang; secondly, to furnish parallels between the recorded variations of the muscular system in man and the arrangement of the muscles in the Quadrumana; and thirdly, to show that the Quadrumana differ among themselves in those points in which they differ from man: the distribution of the Flexor Longus Hallucis and Pollicis, for instance, differing as widely in the Orang, from that found in the bulk of the Quadrumana, as it does from that which obtains in man.
Unfortunately, comparative anatomists have almost exclusively confined their investigations to the osteology and nervous system of the Bimana and Quadrumana; and, while they have frequently noticed the approach which the lower races of mankind make to the quadrumanous type in those parts of their organization, few or no inquiries have been made into the myology of these races, and consequently the abnormal variations here mentioned are exclusively obtained from civilized races.
In many of the wild races, the external form of the limbs differs slightly from that of the civilized ; and I think it may be fairly pre-
