i 4 THE SCOTTISH NATURALIST 



indicating their relative position according to the squares in 

 Professor Thompson's Fig. I, but separating the captures 

 made in each season. The figures in each case give the 

 number of fish, the number of the month, and the year. 

 Thus, in the upper part of the table in square XIII "2.6.09" 

 means that two Chimaerae were caught in June 1909. It will 

 be seen that when presented in this way the evidence points 

 as much to an easterly as a westerly migration. 



It will be observed also that the records arrange 

 themselves into a western summer and an eastern winter 

 group. The captures made in the western half of the region 

 are remarkably consistent. They serve to indicate that from 

 May or June to September a number of Chimaera arrive each 

 year north-west of Scotland. Professor Thompson says they 

 come from Norway. I venture to say that the evidence 

 points to their coming from the Atlantic. 



Professor Thompson was informed by Holt that most of 

 the Irish captures were made in Ma)'. It is evident from 

 the particulars he has gathered that the)' reach Iceland from 

 April to June. This goes to show that there is a migration 

 of Chimaera in spring and early summer to the continental 

 slope and plateau, and that the migrants reach the north- 

 west of Scotland from May to September ; in small numbers, 

 certainly, but it must be recalled that they come in that 

 region into the shallow water of the Wyville Thomson ridge, 

 which still acts if incompletely as a barrier, and that the 

 distribution north of Scotland and Norway is a relatively 

 modern feature being post-Glacial in origin. 



The annual denatant migration of Chimaera in the 

 Atlantic, as we may infer from parallel cases, is a general one 

 affecting the population as a whole, and the distances 

 travelled will vary according to size and condition. The 

 younger fish will make a short migration and return at an 

 earl\- period. On the other hand the mature fish approach 

 and ascend the continental slope in successive shoals over 

 a wide season, probably from early in the year to autumn, 

 possibly all the year. After spawning the fish will continue 

 their denatant migration to recuperate. These are the fish 

 which I venture to think will be found to migrate to the 



