— 18 ^ 



ation. If it is necessary, however, to further test the correctness of a determination, the 

 specimens should be cleared (e. g. in xylol, see p. 9) and the number of vertebrae counted. 

 The number of vertebrae I have found in a large number of adult cod can be seen from 

 the following table. 



Number ef verte bvœ in Gadus callarias 



Suminary 



We see from this that of the 236 cod in which the abdominal and caudal vertebrae 

 were distinguished, there was only one which had more than 19 abdominal vertebrae, 

 namely 20. From the list given on p. 35 of the number of vertebrae in the coalfish it 

 will be seen, that the smallest number of abdominal vertebrae found in this form was 23. 

 Thus by counting the abdominal vertebrae (the caudal need not be considered), we have 

 an excellent means of distinguishing between Gadus callarias and virens, if all other 

 marks fail. 



§ 2. General features of the occurrence 



It should be mentioned first of all, that the chart of distribution I only holds good 

 for the months April, May and June. Later in the year the young of the cod, at least 

 in the southern parts of the region investigated, cease to live pelagically and we should 

 therefore obtain an incorrect picture if we include all the numerous negative stations for 

 July, August and September. For Iceland, however, some special charts are given, which show 

 the distribution of the young pelagic cod both before and after July 1904 (Charts IX and X). 



It is so easy to determine the eggs of the cod with certainty by hatching them out,' 

 that I have been able, in preparing the charts of distribution, to have regard not only for 

 the postlarval young but also for the eggs. In representing the occurrence, when eggs but 

 not young were found at a station, the station is marked not by a black dot as usual but 



From tbe presence of 3 postanal pigment bars. 



