300 ACCOUNT OF THE RIBBON FISH 
gestive cavity. The organ is partially and unequally cleft by a 
median fissure, the left side being larger than the right. Its 
tissue is reddish brown, spongy and friable. The posterior end 
of the kidney tapers to a point. The anterior end also tapers a 
little, but isrounded. The ureter enters the under surface of the 
gland, and terminates by opening into the general cavity which 
exists along the median line of the organ. Along the upper 
angle of this cavity and elsewhere are the openings of small 
canals bringing the secretion from the uriniferous tubules. These 
last can be readily seen with a common magnifying glass. 
The supra-renal glands, fig. 3 p, are two small ovoid bodies, 
much paler than the kidney, partially imbedded in that organ 
on its upper surface, at a distance of two inches from its posterior 
extremity. There is no trace of air-bladder. 
The heart, which is double the size of that of an ordinary cod- 
fish, occupies a spacious triangular cavity. Its ventricle is large, 
firm, and triangular. The bulb of the aorta is smaller than that 
of the cod. The auricle is capacious and of irregular form. 
The blood-vessels beyond were not examined, and we could not 
investigate the nervous system. 
In a little blood obtained from the heart, the blood-discs, Pl. I: 
fig. 5, are found to vary much in size, and also in form from sub- 
circular to elliptical and even fusiform, having their extremities 
or poles somewhat pointed. The nucleus is generally large and 
distinct, and presents several nucleoli of different sizes, giving it 
in many instances a granular appearance. 
General remarks.—Having referred to what we have been able 
to find recorded respecting the genus Gymmnetrus, we found that the 
figures as well as the descriptions of the external parts were very 
imperfect, and the anatomy little known; hence we thought 
it desirable to make the above description fuller than otherwise 
would have been necessary. Seven or eight species only have 
been recorded. Cuvier and Valenciennes, in vol. x. p. 365 of 
their ‘ Histoire Naturelle des Poissons, describe one species from 
a manuscript in the library of Sir Joseph Banks, which is pro- 
bably identical with ours, and to which they have given the 
name of G. Banksti. It was thrown up at Filey Bay, March 18, 
