Beattik. — On the Anatoini/ of the Bed Cod. 79 



irregular longitudinal bands — the right one being the narrower 

 — which pass at the anterior end into two brownish-red 

 bodies, which lie dorsal and also partly anterior to the anterior 

 end of the air-bladder. These improperly-called head-kidneys, 

 to which I will refer again, come in contact with the posterior 

 end of the skull, and also lie to some extent on its dorsal sur- 

 face under the muscles. These bodies are the remains of the 

 original pronephros. The remaining part of the kidney is nieso- 

 nephros. At the posterior end the longitudinal bands— the 

 middle kidney — unite and form a median mass lying posterior 

 to the air-bladder, and enclosed in the first haemal arch. This 

 posterior kidney bends forwards and passes forwards and 

 downwards for about liiu. or 2in. From this part of the 

 kidney goes off the ureter. Narrow at its posterior end, it 

 widens to form two pouch-like diverticula — the urinary 

 bladder, — and again gradually narrows to its opening behind 

 the anus. The great difference between the kidney of Lo^cZZo 

 and that of Gad us as figured by Smith and Norwell, in their 

 " Illustrations of Zoology," is seen in one of the middle 

 kidneys of Lotella being narrower than the other, and also 

 in the presence of the great posterior kidney which extends 

 into the abdominal cavity below the air-bladder. This part 

 seems to be entirely absent in Gadus. A microscopic exami- 

 nation shows that the middle and posterior parts of the kidney 

 have the usual structure ; but that the so-called head-kidney 

 is absolutely devoid of kidney structure. The whole is com- 

 posed of an aggregated mass of rounded very small cells, 

 which, unlike the corpuscles seen in the blood-vessels, do not 

 fit closely into one another. TJie structure is that of a simple 

 lymphatic gland. Balfour, in the " Quarterly Journal of 

 Microscopii. Science," vol. xxii., 1882, has described the 

 •same structure in several other fishes, with the exception 

 that he found kidney tissue mingled with his lymphatic 

 tissue. 



Ovaries : These are two conical bodies uniting with one 

 another posteriorly, and lying one on each side in the j)Osterior 

 part of the abdominal cavity. The ovaries send off from their 

 posterior ends a common duct, which runs parallel with the 

 ureter, and is separated from it by a very thin wall. The 

 oviduct opens to the outside between the anus and the urinary 

 aperture. The cavity of the ovary is filled with plate-like 

 bodies, which are prolongations of its walls, and from the 

 epithelium of which the ova are formed. 



Of the male organs I can say nothing, for in working up 

 this paper I never came across a male. This was no doubt 

 due to the fact of the great preponderance of female fishes over 

 males— a fact vouched for by Dr. T. W. Fulton in Geddes and 

 Thomson's " The Evolution of Sex." 



