258 PHILOSOPHICAL TRANSACTIONS. [aNNO I698. 



vessels was bestowed on the cormia uteri. Near the ovaria were observed the 

 fimbriae foliacese, and from thence a passage into the tubae fallopianae, which 

 were two fine slender canals or ducts, supported by the alae uteri, and running 

 waving, and leading into the extremities of the cornua uteri. Tlie cornua 

 uteri, being inflated, were about the size of a goose quill, about 1 i inch long, 

 and were fastened to the alae uteri, towards both ends a little bent ; but where 

 they pass into the uteri, tiiey were reflected inwards ; at the other extremity 

 reflected outwards. Their substance seemed rather thicker than the uteri them- 

 selves, and not so transparent, by reason of the numerous blood-vessels which 

 irrigated them almost all over; for in the inside, both above and under, there 

 ran, the whole length of the cornua, large trunks of blood-vessels, sending 

 from the side all along numerous branches ; which is very requisite in animals 

 tliat are multiparous, as is our subject, as the litter lie, and are formed in 

 the cornua uteri. And I here observed some little risings of the internal mem- 

 brane of the cornua, by which they were somewhat divided into cells, but very 

 imperfectly. These 2 cornua empty themselves into the 2 uteri, just in the 

 middle, where they are conjoined together ; and so outwardly seem to form, 

 as it were, but one continued body ; from this conjunction, near the neck of 

 the bladder, extending themselves on each side, and afterwards being reflected 

 to the neck of the bladder again, where they pass into the vaginae uteri. But 

 having extended this part by inflation, and so letting it dry, and then dissecting 

 it; I observed a membrane like a diaphragm, to run perfectly across, and 

 entirely to divide them, near the insertion of the coriuia, into two distinct 

 ■bodies ; so that what is contained in the uterus on the right side, cannot pass 

 into the uterus on the left side, on account of this partition ; though outwardly 

 tiiey both seemed but as one continued body. The fabric of this part seemed 

 very surprising ; and such as I have not met with the like, in any animal besides ; 

 at least of the quadruped kind.* It is true, in lobsters and crabs, in the female 

 there are two uteri, as in the male there are two penes, but more distinct and 

 separated from each other. So two penes, and each forked too, I have observed 

 in the rattle-snake (Phil. Trans, N° 144, Abridg. vol. ii. p. 570) ; but how the 

 male possum is provided, I cannot tell : but this I think is the only instance of 

 a land quadruped that has two uteri ; and each of these too seemingly double, 

 by that reflection they make, and by an imperfect diaphragm, which divides the 



* It was scarcely possible for Dr. Tyson, though a most expert anatomist, to determine with 

 exactness the structure and uses ot all the parts of that comphcated viscus, the uterus, in the opossum- 

 tribe from a single specimen, and that too in the unimpregnated state. It is therefore recommended 

 to the reader, to compare this description of the uterus of the opossum witli the description and 

 figures of the uterus of tlie kangaroo (so nearly allied to it) by Mr. Home, iu the Phil. Trans, for 

 1795. Such a comparison will throw much light on the pueient subject. 



