392 R. S. CLARK. 



CONCLUDING REMARKS. 



The Tables of tlie occurrence of the various species with the number 

 and size of individuals show that all those recorded spawn either in the 

 immediate neighbourhood or at localities not far distant. 



It may be of interest to note here the capture of the young stages of 

 those adult forms which have approximately their most northern limit 

 of distribution in Plymouth waters.* 



The spawning period is definite for most of the species, though in 

 cases such as the sprat and dragonet, it is prolonged indefinitely over a 

 considerable part of the year. In closely related species of the same 

 genus there may be wide variation in the length and time of spawning. 



One of the most interesting problems suggested by the study of the 

 distribution of pelagic larval and post-larval forms is the question 

 of the nature of the causes which bring about the movements of 

 young fishes from the inshore to the offshore waters and vice versa. 

 There appears to be evidence in favour of the view that in some localities 

 these movements are the result of inshore and offshore currents which are 

 not constant and which seem to vary according to the prevailing winds. 

 In narrow waters like the English Channel, the currents are doubtless 

 modified by the general set of the main currents from the Atlantic, and 

 by the contour of the coast-line. In addition, the tidal streams tend to 

 make conditions more complex. The present records bring some evidence 

 to bear on the matter. For example, pelagic larval and post-larval 

 forms of Ctenolahrus rwpestris, an inshore spawner, occurred in the waters 

 south of the Eddystone rocks, while similar stages of Solea variegata, a 

 deeper water type, were taken in comparatively shallow areas. The whole 

 question is one of great interest and might well repay further investigation . 



The vertical distribution of the young was found to vary considerably 

 during day and night hauls. The latter yielded a much larger per- 

 centage of young forms from the surface layers. 



Finally, incompleteness in the study of the Clwpeidce, Ammodytidw, 

 TriglidcB, Bothinoe, Gobiidce, and BleniidcB must be acknowledged, but 

 these are now receiving special attention. 



REFERENCES. 



Ehrenbaum's two volumes on " Eier und Larven von Fischen " in the 

 Nordisches Plankton series, Lief 4, 1905, and Lief 10, 1909, have been used 

 extensively in the present work, both for the description of species and in 

 the references to papers published previous to 1909. 



* Since this paper went to press, the larvse and post-larvae of Serranus cabrilla have 

 been identified from the 1913 material. I am indebted to Prof. Ehrenbaum for 

 confirmation of my identification. 



