29 



the depressores labii superioris and levator es labii inferioris were 

 found of considerable breadth and strongly developed : their action 

 in protruding the lips in a conical form has been frequently noticed 

 b}' those who have had opportunities of observing the living animal. 



The platysma myoides is of greater extent than in the human 

 subject, and some of the fibres have a different direction, bearing a 

 resemblance to the cervical portion of the panniculus carnosus in 

 some quadrupeds, as the Beaver and Guinea-pig. 



The muscles of mastication, and the articulation of the lower jaw 

 were described. 



The digastricus has not any connection with the os hyoides, the 

 anterior fleshy portion being altogether wanting in the Orang Utan, 

 It is inserted by a strong round tendon into the angle of the lower 

 jaw. This circumstance is interesting in connection with the me- 

 morable dispute between Dr. Monro (primus) and the French ana- 

 tomists, concerning the actions of this muscle; and it is remarkable 

 that Winslow, with his accustomed ingenuity, should have alluded 

 to such a disposition, in illustrating his opinions of the actions of the 

 digastricus on the lower jaw in the human subject. Some peculiarities 

 in the mylo-hyoideus, genio-hyoideus, and omo-hyoideus were noticed. 



The peculiar muscle discovered by Tyson in the Chimpanzee, and 

 called by him levator claviculce, arises in the Orang Utan from the 

 occiput and transverse process of the atlas. In the Chimpanzee 

 which Mr. Owen dissected, he also found it arising from the trans- 

 verse process of the atlas, and not from the second or third cervical 

 vertebra. It is inserted broadly into the humeral extremity of the 

 clavicle. 



Neither in the Orang Utan nor in the Chimpanzee is there any true 

 ligamentum nuchce. The part commonly so called in the human 

 subject, consisting also in these animals only of the inelastic com- 

 missural tendons of the trapezii, the rhomboidei and the serrati 

 postici superiores. To give additional support, however, to the head 

 of the Orang Utan, which preponderates so far anterior to the oc- 

 cipital foramen, the origins of the rhomboidei are extended upwards 

 to the occipital bone, to which they broadly adhere, beneath the 

 trapezii. In the Chimpanzee this disposition does not occur, but 

 in both animals the rhomboideus is a single muscle, without division 

 into a greater and lesser portion. 



Three muscles supply the place of the pectoralis major in the 

 Orang Utan. Their proportions and attachments were minutely 

 described ; and while speaking of these with reference to each other, 

 it was found convenient to apply to them the names of sterno- 

 humeralisy costo-humeralis, and sterno-costo-humeralis. 



The reading of the remainder of this part of the anatomy of the 

 Orang Utan was postponed to a future meeting of the Committee. 



Several species of Birds belonging to the collection recently 

 made by Capt. Philip P. King, R.N., during his survey of the Straits 

 of Magellan, were exhibited. Other birds from the same collection 

 had been named and characterized at the Meeting on the 14th of 



