VOL. XIII.] PHILOSOPHICAL TRANSACTIONS. 6/3 



less we deny them to have any heart at all. For in a leech, there are two large 

 arteries, without any of these swellings ; so we must either confess them to bq 

 two hearts, or not to have any ; for there is no part I have yet observed in 

 them, that I can give that name to, besides ; nor to these without some 

 allowance. 



We come now to what seems most peculiar to this animal, to be met 

 with in none besides, viz. the glandulous body seated on the ridge of the 

 back, just over the hinder legs, but so covered by the long bristles there, that 

 it was not to be observed but by opening them with the hand, and then appears 

 a space almost bare, only beset with a few shorter and finer hairs; and in the 

 middle of it is the protuberant orifice of the gland, by which it discharges the 

 liquor which is separated by it within. This orifice has its lips a little reflected, 

 and protuberant above the surface of the skin. It would easily admit of a large 

 probe, which could be turned into several parts of the gland. On a gentle 

 pressure with the finger, there was observed a small quantity of a white yel- 

 lowish juice, and some part of it of a little darker colour, which yielded a very 

 pleasant and agreeable scent, much like that of musk or civet. The gland 

 itself was seated between the skin and some part of the panniculus carnosus. 

 For in the middle of that part or surface which regarded the back, it was bare, 

 and not covered with that muscle, only the edges inclosed within it; so that in 

 taking off the skin, the gland too could easily come away with it; however, 

 this muscle may be assisting to it, by its contractions, in pressing out its liquor, 

 as the sphincter muscle is to those scent bags placed at the extremity of the 

 rectum of other animals. The gland was conglomerated, or made up of several 

 minute and small white glandules. It had no considerable cystis or cavity with- 

 in ; but like the pancreas, or salival glands, it had abundance of excretory ducts ; 

 which terminating at last in one, discharged its separated juice by the common 

 orifice. This orifice having something of a resemblance to a navel, has imposed 

 upon almost all who have described the animal, as to believe it an umbilicus; 

 and others, who have deviated from this sentiment, have delivered quite as 

 absurd and extravagant conjectures about it. 



But my opinion concerning it is, there is nothing I can compare this gland 

 with more than those scent-bags or glands in other animals. For though the 

 whole body may be perspirable, and so diffuse a smell, yet that peculiar fioetor, 

 which is observed in all strong-scented animals, I have hitherto constantly found 

 more remarkably collected into one part ; the particles, which cause it, being 

 separated from the mass of blood by peculiar glands, which either quickly dis- 

 charge it wholly out of the body, as in some, or transmit the separated juice 



VOL. II. 4 R 



