AND CIRCULATION IN FISHES. — 1:89 
füpplies the numeros and: large inufcles and fins on the fide 
of the fish; as far down a$ the fins near to the anus, 
19. At laft to the £rum& 'T. before menticned, is added 
a large, vein X, on each fide, which conveys the blood from 
the under vein S of the fourth gill; and both veins V. W, of 
- the fifth gill (/); and we are led by it to a great veffel Y, which 
pow aílumes. plainly the office of an artery refembling out 
' aorta defcendens, 
| 40, From the fore» part of this trunk two large branches 
-. €, d, analogous to our car/iac and mefnteric arteries, are fent 
offto the chylopoietic vifcera; a fmall branch from which en- 
ters the liver, refembling our £epatic artery (m). 
| 21. From the fides of the aorta the organs of generation 
and urine are fupplied by fimall arteries e. e. v. e. etc. and from 
- the lower part of the trunk are fent of two lateral branches f. 
Jf. that-may be compared to our ifiac arferiet, and which fup- 
ply the mufcles and fins at the lower part of the body. 
22. À middle arferg g runs flraight down into the teil - 
covered and protecled by cartilage and terminates the aortic 
fyflem, . | : UR 
: 23. From the remarkable courfe of the arteries of the 
heart and. of the branchial and hepatic arteries, fimilar to that 
$n man, we fee clear proof, that the blood, which, after pas- 
fing through the gills, has undergone one circulation, or ra. 
ther here has paffed through one artety and one vein, is unfit 
for fome office or offices, which are performed by the blood 
in the heart, gills and liver, - 
24, Nutrition only has been mentioned by authors; but 
3 fully fatisfying reafon has as yet been given, why by one 
tirculation. the blood fhould become unfit for this purpofe; 
Aa 3 and 



(7) "Tab. 1. fig. 5. ; 
n) "Yab, HII, R, S, T. U. V. W. 
