52 



recorded by Schmidt of the larvse in the region where the eel larvae 

 were procured that the larvse are transoceanic in distribution. 

 Nevertheless the records of the occurrence of the egg-bands as 

 far south in the North Sea as off Northumberland shows that 

 spawning occurs in the northern North Sea at least. When 

 they arrive in coastal waters they still migrate contranatantly, 

 and they form, for example, a regular feature of the summer 

 population of the Northumberland coast. The seasonal migration 

 of the immature we know, but the spawning migration is usually 

 evidently a long contranatant one.* 



Spur Dogfish. — In the early days of the Northumberland 

 experiments young spur dogs, Aacnthias vulgaris, were obtained 

 in shallow water at the trawling stations in fairly large numbers. 

 This was certainly the fact in 1893 and 1896, but since then they 

 have not been observed. The records point to the females migrat- 

 ing inshore to liberate the young, but that usually they do not 

 migrate so far inshore as in the years mentioned. They were 

 simply recorded as " small,*' but the size was such as to indicate 

 they were in their second summer for the most part. The young 

 of the year were procured inshore at Hartley in November, 1896. 

 The species has not, however, declined in numbers. We have 

 frequently observed that large numbers have been landed by 

 trawlers, and of a size which points to the young not migrating 

 so far inshore. On August 25th, 1911, the North Shields trawlers 

 had large catches from the grounds about eight miles off the coast. 

 One of the vessels had from three to four cartloads, and in 

 another the gear was broken when hauling the catch on board. 

 Again, in 1915, large numbers of spur dogs were landed during 

 the latter part of the year, and especially in October. Most were 

 obtained about 70 miles north-east by east of the Tyne, smaller 

 numbers from the North-East Bank and still smaller numbers 

 nearer the coast. A sample was measured and was found to 

 consist of 50 males, 24 to 31 cm. in length, and 12 females, 20 to 

 28 cm. in length. They were therefore small in size and young 

 fish, but it is interesting to note that even so marked a segregation 

 according to sex was manifested. The segregation of the adult 

 females is understandable from the fact that they migrate inde- 



* 1920.. Bowman. Fish. Bd. for Scotland. Sc. Invest ,1919, No. 1. 



