398 . Professor W. C. McTntosli [Feb. 1, 



fclie occiput, for tlie blood-vessels there sliine tlirough tlie tissues, 

 whicli generally are more translucent than in the green cod. 



Prof. G. 0. Sars considered that about this stage there was an 

 intimate connection between them and the hordes of medusae (^Aurelia 

 and Cyaned) which abound in the inshore waters towards the end of 

 summer. He thought the young cod aj^proached the medusa for the 

 sake of the minute pelagic animals stupefied by its poisonous threads, 

 and that the fish repaid this favour by picking off a parasitic crustacean 

 {Hyyeria medusaruiii) vfhich. clings to the medusa. Observations, con- 

 tinued for a long period in this country, however, show that this 

 connection is only casual and of very little im^Dortance, and that 

 certain Hyperise are occasionally found in vast numbers in a free 

 condition. 



As the season advances, the young cod are joined off the rocky 

 ledges by a few pollack and whiting, but not by the haddock, which 

 appears to have certain social views of its own — keeping probably a 

 little farther out. The size of these cod late in autumn, as in 

 October, varies, some reaching 4 to 5 inches in length. Their 

 food ranges from zoophytes to crustaceans, mollusks, and small fishes, 

 and in confinement the larger are voracious, an example about 5 

 inches readily attacking a smaller (3 inches) and swallowing it as 

 far as possible, though for some time a considerable portion of the 

 body and tail of the prey projected from the mouth. Moreover, the 

 tessellated condition becomes less marked, and as they approach 

 8 inches in length a tendency in some to uniformity of tint is 

 noticeable. Many of those, however, that continue to haunt the 

 rocky shores and the tangle-forests beyond low water still retain for 

 some time mottled sides, and they are known by the name of rock- 

 cod. Further, while their growth in the earlier stages is less marked, 

 it is now^ very rapid — even in confinement. The exact rate of growth 

 in the free condition in the sea is difficult to estimate, but the little 

 cod of an inch and a half to an inch and three-quarters in June reach 

 lengths varying from 3 to 5 inches in autumn, and in the tanks of 

 the laboratory, specimens 5 inches in August attain 8 inches the 

 following March. At Arendal, in Norway, where o23portunities for 

 watching the growth of cod in confinement have been supplied with a 

 liberality yet foreign to our country, Dannevig found that the cod of 

 3 mm. in April reached only 15 mm. in June, a length somewhat at 

 variance with the condition, as above stated, on our shores. In July 

 they measured 2 inches, in September 3 inches and a half, and in 

 October about 4 J inches. The second year they attained 14 to 16 inches 

 in length. In artificial circumstances, as well as in nature, it is found 

 that great variation exists in the sizes of the young fishes of the same 

 age, and this variation would not seem to be related to temperature. 



At the stao'es just mentioned they now come under the notice of 

 both liner and trawler, for young cod 5 or 6 inches in length 

 occasionally take a haddock-hook, and those somewhat larger 

 (9 to 18 inches) occur in certain hauls of the trawl, especially off a 



