570 PHILOSOPHICAL TRANSACTIONS. [aNNO 1682-3. 



Aldrovandus*, and others, who perhaps misled him in the account of these 

 parts. Nor as to the other extremity are they more in the right, which by their 

 picture and description, they make to be altogether single, and covered and 

 quite beset with prickles like the skin of a porcupine. Whereas this part in 

 vipers too, as well as in the rattle-snake, divides and forms two large round 

 bodies, or two distinct penes. And this Baldus, or rather Camentius, who made 

 the dissection for him, seems to have observed where he says, Quando turgidi 

 fiunt, aut extra violenter emittantur, uti saepe apud Paulum vidimus, pene banc 

 formam referre Y aspectu aspero ut Erinaceus. For in vipers they are hispid to 

 the end ; but not in the rattle-snake, as is plainly represented in the figures 

 of both. 



There are several animals which have no penis at all, but vasa deferentia, as 

 most fishes. The rattle-snake and that family have these organs of generation 

 the most numerous of any I have hitherto met with. But why the male rattle- 

 snake, or the male viper, should have 4 penes, when the female has but 2 

 uteri for receiving them, seems a difficulty to me. Amongst many conjectures 

 I have had about it, what seems the most to satisfy me, is this: that they have 

 the penis here on each side double^ or forked, that so being entered the uteri, 

 by spreading themselves like the pythagorean Y, they may the better and more 

 firmly be retained there till they have performed their duty. And this too seems 

 one use of the aculei or bristles towards the root of them ; for having their 

 points looking backwards when once they have entered the pudendum, they must 

 needs lock them in, and retain them there, till such time as the parts being 

 tired, and subsiding, have leave to retreat. For in animals which have no ve- 

 siculae seminales, it is requisite that the coitus be long, that so the seed which 

 cannot quickly, may leisurely be transmitted from the testes: but where it is 

 beforehand stored up in the vesiculas, there the coitus is soon over; but when 

 they must expect the generation, or at least a sluggibh descent of it, nature 

 makes provision for the more convenient performing it. So in dogs, which have 

 no vesiculae seminales, near the root of the bony penis, there is a large body 

 made up of an abundance of cells and vessels, which upon the rushing in of 

 the blood and spirits, is so mightily extended and swelled, that it forcibly keeps 

 him in, until such time as the impetus be over, and the part subsides. There- 

 fore in the rattle-snake, (where, as we have observed, there are no vesicular, 

 and where the vas deferens is all along crimpled and winding, and so upon both 

 accounts must be thought to be long in coition) the contrivance and structure 

 of these parts seem very requisite. For although in this action they twist their 



* Aldrovandus de Serpent, et Dracon. — Orig. 



