ORDER CARNASSIER. f 



sophical Transactions for 1795, in which he states this 

 remarkable fact ; that the foetus of pouched animals ex- 

 hibits no trace of the umbilical cord. Barton proceeded 

 immediately to the authentication of this point, by exam- 

 ing young opossums in the pouch, and found it correct. He 

 supposes, however, that this umbilical cord will be dis- 

 covered on individuals in the uterine gestation ; but his 

 researches not enabling him ever to have seen a fcetus in 

 the uterus, he gives himself up to theoretical conjectures. 

 He proposes to refer the mode of generation peculiar to 

 the Didelphes, to that of reptiles and fishes, which, he 

 believes, are also without the umbilical cord. 



Dr. Barton furnishes a testimony in contradiction to 

 the assertion of Camper, that man is the only animal ca- 

 pable of lying on his back. This, he says, often happens 

 to the female opossum, especially when she has young 

 ones. Lying on her back, she can touch, with the ex- 

 tremity of the vagina, every point of the interior sides of 

 the pouch, and consequently the little ones, at the moment 

 of birth, are protruded into the pouch without difficulty. 



Foetuses, without any trace of the umbilical cord, which 

 yet have the nostrils widely opened, and the lungs con- 

 siderably developed, would seem to countenance the opi- 

 nion of a different system of organization from other ani- 

 mals. M. de Blainville, in an article on the generation 

 and foetus of the Didelphis, verifies the facts stated by 

 Barton. He was unable, after the strictest examination, 

 to discover any umbilical vein or artery, nor even the 

 suspensory ligament of the liver. The gland of the ethy- 

 mus was also wanting, and, generally speaking, none 

 of the arrangements observable in the fcetus of other 

 mammiferous animals, such as circulation and respira- 

 tion depend on, are found here. From these facts, M. de 

 Blainville agrees with Dr. Barton pretty nearly. " There 

 are," he says, " two sorts of gestation, one uterine, 



