of the Fishery Board for Scotland. 125 



Distribution of the Gadidce. 



Hoek gives the distribution of the Gadidse in northern waters in his 

 catalogue of fishes of the North of Europe. 



The Young Stages oj the genus Gadus. 



The young stages have been described by many authors. The subject 

 has been comprehensively dealt with lately by Schmidt. He has 

 described many stages of the following species : — Callarias, virens, 

 pollachius, eeglefinus, merlangus, luscus, minutus, poutassou, argenteus, 

 esmarki. 



The Stomach and the Gut. 



The stomach is capable of great distension and extension. This is 

 specially noticeable in virens. When gorged the stomach may extend 

 well back into the hind abdomen. When the reproductive organs are 

 large, however, they tend .to prevent the full distension of the stomach. 



The gut forms a loop in the hind part of the abdominal cavity. It 

 goes backwards on the right side of the body and returns on the same 

 side. The end of the loop is free in the cavity. Sometimes the loop 

 goes round the end of tho abdomen and extends forward for a little way 

 on the left side (fig. 98). This condition was noted in some specimens of 

 the following species : — Callarias, seglefinus, esmarki. 



The Mesentery in Virens. 



The mesentery is continuous with the peritoneum lining the posterior 

 end of the abdominal cavity. It divides the hind abdomen longitudinally 

 into two from the floor to the roof, binding the ureter to the hind lobes 

 of the ovary and the latter to the roof of the cavity. 



Proceeding anteriorly, it splits into two, giving a mesentery to each of 

 the free anterior lobes of the ovary. Each lobe is thus supported 

 separately to the roof of the abdomen. In front of the anus the 

 raesenteiy is attached to the rectum at the beginning of the ovarian lobes, 

 but anterior to this point it has no connection to the ventral surface. 

 The spleen is supported by a median mesentery, and is often found lying 

 between the lobes of the ovary. 



Notes on the Species. 



Callarias. — A prominent character in this fish is the broad fan-shaped 

 tail fin. Its hind edge is convex. In the small cod the tail is slightly 

 different in shape. In two specimens, 23 cm. and 38 cm. respectively, 

 the hind edge was straight across. In two others, 25 cm. and 28 cm., 

 there was a slight concavity in the hind edge. 



The ureter left the kidney at the transverse process of the vertebra in 

 front of the first hsemal arch. 



The cod sometimes exhibits a small angle in the anterior edge of the 

 orbit. 



JEglefinus. — This species has a large eye and a small mouth. 



In the large haddock, e.g., from Iceland, the scales are large and the skin 

 is tough and hard. 



The barbel is stumpy, with a bulbous base. 



The first dorsal fin has a characteristic shape in this species. It is 

 I 



