1902.] NATURAL SCIENCES OF PHILADELPHIA. 253 



that while Galeopithecus may "resemble or differ from Lemuroidea, 

 Rodentia, lusectivora or Chiroptera, nevertheless it presents so 

 many peculiarities in its organization that it stands by itself. No 

 one doubts that a Petauris is a marsupial, a Pteromys a rodent, a 

 Propithecus a lemur, a Pteropus a bat, even though they all are 

 provided with a patagium resembling more or less that of Galeopi- 

 ihecus, by means of which they fly or dart through the air. 

 Galeopithecus, however, stands alone; it is sui generis. To no 

 order can it be referred unless to some hypothetical extinct one, 

 fossil remains of which have not yet been discovered. The most 

 plausible view as yet advanced as to the affinities of Galeopithecus 

 with the mammals with which it has been usually associated is to 

 suppose with Leche'-" that there once existed, in remote Mesozoic 

 times, an order of mammals of ungulate character from which 

 have descended Galeopithecus, the Chiroptera, Lemuroidea and 

 lusectivora. Certain facts otherwise difficult to explam become 

 then intelligible. For example, if the lemurs of the present day 

 have descended from Eocene lemurs like Adapis, Anajotomor- 

 phoris, Tomitherum, Hyopsodus, Notharctus,^°, generalized forms 

 combining ungulate with quadrumanous characters, certain peculi- 

 arities of their alimentary canal and their non-deciduous diffuse 

 placenta may be explained as being due to inheritance from remote 

 imgulate ancestors. Further, the fact that the condyle of the jaw 

 is situated nearly on a line with the teeth in Galeopithecus, Chiro- 

 mys, in certain lusectivora and Chiroptera, as in the Diplocynodon 

 and kindred mammals, the Pantoiheria of Jurassic times'^ points to 

 the same conclusion. Accepting the above hypotheses as provision- 

 ally correct, it follows that the herbivorous character of the alimen- 

 tary canal of Galeopithecus is due to inheritance from an ungulate 

 ancestor, whereas its patagium has been acquired in some unknown 

 way through adaptation. Were it not for the combination of the 

 above characters, Galeopithecus would have become long since ex- 

 tinct in the struggle for life with its contemporaries, the lenuu's, 

 insectivores and bats. 



It appears, at least in the judgment of the author, that Galeopi- 



2» Op. cit., p. 78. 



•^" Cuvier, Ossemcns Fossiles, 1835, T. 5, p. 460 ; Leidy, Report U. S. 

 ■Geol. Survey, 1873, pp. 75, 86 ; Cope, U. S. Geol. Survey, Vol. Ill, 1884, 

 pp. 233-235. 



•"Marsh, Op. cit., p. 335. 



