1018 
SCANDINAVIAN FISHES. 
folds. Beside the termination of the stomach the in- 
testine forms a curve of varying size, with one or more 
small convolutions, before passing into the rectum, from 
which it is divided internally by a more or less distinct, 
annular fold". The liver is generally almost entire, 
having only a more or less deep incision in the hind 
margin. Its length is about 1 / i of that of the abdomi- 
nal cavity proper, somewhat more than V 2 of that of 
the stomach, or 3 / 4 of the distance between the termi- 
nation of the stomach and the vent. Sometimes, how- 
ever, its length is equal to the last-mentioned distance. 
Its upper, concave side surrounds the under side of the 
oesophagus and the beginning of the stomach, as well 
as the gall-bladder, which is rather large and lies to 
the right. The spleen is oblong, rather more than half 
as long as the liver, and is situated on the right side, 
at the fold between the pylorus and the intestine. On 
and Maggi c as testes. The air-bladder varies consider- 
ably in length, between V 2 and 1 / 3 of that of the ab- 
dominal cavity proper. • It is of a pointed fusiform 
shape, but in front, for almost half its length, is divided 
into an upper and a lower cone, the latter joined by 
the pneumatic duct to the oesophagus, though in the 
specimens examined by us the communication has in- 
variably been closed. The kidneys lie, as usual, close 
below the spinal column, above the air-bladder and 
without the peritoneal cavity. They extend not only 
throughout the length of the abdominal cavity proper, 
but also into the backward continuation of the haemal 
canal, in the caudal region, above the prolongations of 
the abdominal cavity, to which structures we shall re- 
turn in our description of the generative organs. The 
urinary bladder lies just behind the downward curve 
of the rectum towards the vent, and has its orifice just 
Fig. 272. Abdominal viscera of Anguilla vulgaris. After Syrski. A, female; D, male. 
A: a , right, b, left ovary; c, right, d, left prolongation' of the ovary in the cando-abdominal cavity; e, septum (prolongation of the mesen- 
tery) between the caudo-abdominal cavities; f, vent; g , urinary bladder; //, fold of adipose membrane on the right side of the intestine; 7/, 
fold of adipose membrane on the stomach; i, fold of adipose membrane on the left side; k, stomach; 7, pylorus; m, liver; 
n, gall-bladder; o, pectoral fins. 
B: a, right, b , left testis; c, right, d, left prolongation of the testis in the caudo-abdominal cavity; e, septum between the caudo-abdominal 
cavities; /, efferent duct of the testes ( vas deferens)', g, seminal vesicle; h, vent; i, urinary bladder, mainly concealed by the seminal vesicle; 
/<:, k', and l, corresponding to h, h ' , and i in A (see above); m, stomach; n, pylorus; o, liver, turned up to show how it is applied to the 
oesophagus and stomach; p, gall-bladder; q, pectoral fins. 
the left side of this fold, as well as on both sides of 
the intestine and rectum, hangs a lobulated peritoneal 
fold, which has been developed into an omentum-like 
fold of adipose membrane, consisting of connective-tissue 
meshes filled with fat-globules. In appearance these 
folds are so like generative organs that they have been 
described both by Ercolani * * 6 and by Balsamo-Cravelli 
a The honeycombed mucous membrane of the intestine and 
part, is apparently subject to considerable variations. 
6 Mem. vAccad. Sc. Bologna, 1872, p. 529. 
c Mem. 1st. Lomb. Sc., Lett. Milano, XII, 1872, p. 229. 
behind the anal aperture. In our common Eel it has 
the form of an equilateral triangle, with one angle (the 
s 
so-called neck) directed downwards and passing into 
the urogenital aperture. 
The generative organs are suspended on each side 
of the abdominal cavity and throughout the greater 
part of its length, side by side with and outside the 
rectum, as well as the thickness of their walls and that of the pyloric 
