SEA-FISHERIES LABORATORY. 107 



Mr. Bailey's identification was based on the conclusion 

 that it could not be anything else, since all the other 

 viscera could be identified. Familiarity with the 

 appearance of the organs in the body cavity of a fish, 

 acquired by seeing very many animals gutted, renders 

 such a "process of elimination" a very certain one in 

 its results. As a matter of fact, the specimen is an 

 interesting example of an ovarian cystadenoma. 



The ovary of a Gadoid fish is a closed sac com- 

 municating with the exterior by a short, wide oviduct 

 (a different thing, morphologically, from the oviduct of 

 such a fish as an Elasmobranch). Numerous lamellae 

 project from the inner surface of this sac radially towards 

 the centre. These lamellae, and the internal surface of 

 the ovarian sac, are clothed with germinal epithelium, 

 and as the ovary ripens the ova form in this epithelium, 

 enlarge, and finally dehisce into the cavity, where they 

 pass through the final stages of maturation. After 

 spawning, the ovary becomes a flaccid, thin-walled, almost 

 transparent sac, consisting of thin germinal epithelium, 

 with, of course, added layers of connective tissues and 

 peritoneum. The extent of alteration in this particular 

 organ can be gathered by comparing this description with 

 Plate IV and Text-fig. 6. 



Plate IV represents, one-half natural size, the whole 

 ovary. When fresh it was a repulsive-looking structure, 

 evidently a mass of cysts of various sizes, and with walls 

 of varying thickness. On cutting into these cysts a clear 

 glairy, albuminous fluid ran out, and the cyst walls 

 collapsed. In many of these cysts were inclusions, two 

 of which are represented as fig. 2 of Plate V. 



Text-fig. represents ;i hand section through ihe 

 middle of the ovary. We see now that it is a hollow 

 sac with enormously thickened walls, in ilie interior of 



