546 
DR. A. GUNTHER’S DESCRIPTION OE CERATODUS. 
or ovary of its side, and enveloped in fat. Each kidney is composed of from eight to 
ten lobes (see fig. 3). The two or three anterior lobes lie on the side of the air-bladder 
(«), by which they are entirely separated from those of the other side ; but behind the 
air-bladder and the vena caudalis ( h ) the lobes of both sides are contiguous and con- 
nected by larger blood-vessels, though the renal substance itself is not coalesced. The 
posterior lobes become smaller and thinner, and, being apposed to the ureters, are again 
entirely separate from each other. 
The ureters ( d , d ') are provided with thick walls, and become superficial in the second 
anterior fourth of the kidney ; they are perforated by only a few primary uriniferous 
tubes ; about half an inch before their termination they externally unite into a single 
trunk, although they remain separate internally, the right entering the left close to the 
single opening in the urinal cloaca (see Plate XL. fig. 2, k ") ; this opening is round, 
dorsad to the genital opening (g"), from which it is separated by a slightly raised wall 
of the mucous membrane. The urinal cloaca (Plate XL. fig. 2, u ) is small, incompletely 
separated from the termination of the rectum ; in fact it may be described as a dorsal 
diverticle of the latter. The urine, consequently, passes by the vent. 
The kidneys are but sparingly supplied with blood from the arterial system, by a small 
vessel ( n ) which descends on the dorsal surface of the intestine, and therefore is one of the 
extreme branches of the arteria coeliaca. On the other hand, a great quantity of venous 
blood is carried to them by venae renales advelientes ( k , k'), which form a portal system 
of the kidneys, such as has been described by Hyrtl in various fishes. I describe here the 
arrangement of the right side, remarking that that of the left differs in several unim- 
portant points of detail, as also probably many individual variations occur. The posterior 
vena renalis advehens comes from the lower parts of the root of the tail, and communicates 
with its fellow of the other side by a short anastomosis lying on the back of the cloaca ; 
it emits (or receives 1) a slender branch to (or from 1) the ureter, and distributes a part 
of its contents by three stronger branches over the posterior renal lobes. Then it enters 
into communication with several intercostal veins (l, l', m), which make their appearance 
through slits in the fascia of the wall of the abdomen, traverse the peculiar cellular 
tissue of that region, and merge into the posterior vena renalis advehens. The hind- 
most of these intercostal veins (Z, l') is much stronger than the anterior (m, m). From 
these veins the middle lobes receive their blood. The anterior lobes are provided partly 
by the remaining portion of the posterior vein, partly by intercostal veins which enter 
the lobes by themselves. There is one pair of venae renales revehentes (i, i ) running along 
the base of the posterior and middle lobes and emptying their blood into the vena cava. 
The blood of the anterior lobes is probably collected in one vein, together with that of 
the posterior lobe of the testicle. 
Organs of Reproduction. 
The generative organs are paired. Their products pass outwards by a paired oviduct, 
or vas deferens. These ducts are entirely separate from the ovaries or testicles, each 
