242 PROCEEDIXGS OF THE ACADEMY OF [April, 



relation to the other forms of mammalian life with which it has 

 been affiliated, and the same jilan will be pursued in the account of 

 the remaining organs. 



Among such peculiarities, as regards the skull, may be mentioned 

 the presence in Galeopithecus of the foramen transmitting the supra- 

 orbital nerve and artery, the division of the lachrymal bone into 

 facial and orbital portions, and the interoi'bital situation of the 

 lachrymal canal. In these respects Galeopithecus agrees closely with 

 the insectivorous Tupaia. On the other hand, in the formation of the 

 tympanic bulla and in the condyle of the jaw being situated at 

 nearly the same level as the teeth, Galeopithecus agrees with bats, 

 Chiromys, as well as certain insectivores. In regard to the vertebral 

 column, Galeopithecus differs from both Insectivora and Chiro^itera 

 in the presence of spinous processes and a pubic symphisis, and in 

 the absence of a ridge on the sacrum and a keel on the sternum. 

 It is an interesting fact that the sacrum, according to Leche,- de- 

 velops caudad — that is to say, ossifies at the expense of the tail, 

 the reverse of which obtains in other mammals. In the presence 

 of an epicoracoid cartilage lying between the clavicle and first rib, 

 and in the epicoracoid element being united Avith the clavicle, and 

 in the elongated character of the scapula, Galeopithecus and Ptero- 

 pus agree. In the splitting of the coracoid into two distinct pro- 

 cesses, dorsal and ventral, the latter the homologue of the coracoid 

 in other mammals, Galeopithecus presents, however, a peculiarity 

 not found in lemurs, insectivores or bats, except in Plpestrellm, in 

 which bat the coracoid, according to Flower,'' is sometimes forked. 

 It is worthy of mention that in both Galeojyithecus and Fteropus 

 the humerus and radius are of the same length in the young ani- 

 mal, the radius becoming the larger of the two bones only as 

 development advances. 



Patagium and Muscular System. 



One of the most striking features in the organization of Galeo- 

 pithecus is its patagium, or the duplicature of the skin that extends 

 from the upper extremity to the head (propatagimn), from the 

 trunk to both extremities (palatopatagium), and from the lower 

 extremity to the tail (uropatagium), covering the whole animal 



2 Op. cit., p. 9. 



' Osteology of the Mammalia, 1870, p. 227. 



