t|)0 fHILOSOPHICAL TRANSACTIONS. [aNNO 1704. 



the breadth of two lines or mure, an edging round the verge of the ear, of a 

 perfect milk white colour. But the ear here being so very thin and tender, it 

 is easily affected by cold or illness, and then this white part becomes jagged and 

 crumpled, as if burnt up, and the whiteness disappears. It is on this account 

 that Margrave, in his description of the tai-ibi of Brasil, which now I take to 

 be the male opossum, says, it has aures subrotundas, molles, graciles, albas, 

 teneras ut charta molles, not that the whole ear was white, but only the edges. 



But what I was most desirous to know was, whether the male had that mar- 

 supium or pouch, for receiving the young, as is affirmed by some. Mr. Cow- 

 per, in the subject he dissected, neither observed the pouch nor the muscles 

 belonging to it, as has been described in the female, nor indeed did I in that 

 I dissected. Only this I observed, when first I had it, that the skin there 

 seemed to be looser; so that with my finger I could easily thrust it in, and by 

 turning it round, could form for the present a pouch ; but this would easily 

 turn out again, on withdrawing my fingers. Whether therefore it is capable 

 of being formed into a pouch or marsupium on occasion, I shall leave as a query 

 to be resolved by those that live where they breed, whether they ever observed 

 the male to receive the young ones as the female does? However, in the male 

 there were those bones I call marsupialia; and I observed muscles running from 

 them to the hinder legs, which doubtless are very serviceable to them in draw- 

 ing up their bodies, as I find Mr. Cowper has likewise remarked. 



I shall further add, to confirm what Oppian and others write concerning fishes 

 receiving their young ones into their bellies, that Mr. Herbert, in his Travels, 

 lib. 1, p. 23, says, that in their voyage they took a shark 9^ feet long, and 

 found in her paunch 55 young ones, each a geometrical foot in length ; all 

 which, he adds, go out and in at pleasure. 



As to the brain of the opossum, I observed that being taken out of the cra- 

 nium it weighed 2 drams 2 scruples. I did not find either in the cerebrum those 

 anfractus, or in the cerebellum those circilli which we usually meet with in other 

 brains. The whole was of an oblong figure, and seemed to be divided into 

 three parts, viz. the cerebellum, the cerebrum, and that part of the cerebrum 

 which was projected into the rostrum. For by the pinching in of the cranium 

 here, the fore part of the cerebrum, from whence issued the processus mamil* 

 lores and olfactory nerves, was by this constriction remarkably distinguished 

 from the cerebrum; like an anterior brain. In the vermin kind, and those that 

 have a long rostrum, I have observed the like. For nature here seems to give 

 them more particularly the advantage of the sense of smelling, for finding out 

 their prey, or avoiding the danger they would shun. 

 T i observed the optic nerve and the eye to be large, the better to look out for 



