744 Proceedings of the Royal Irish Academy. 



the relative proportion "being about the same in both. While Tve have, 

 'doubtless, still much to learn as to the causes -^hich influence the 

 ■distribution of the free -swimming fonns of Copepods, we can hardly 

 now expect to add veiy many to the number of those already known, 

 •■although we may easily add many to the ah'eady recorded species of 

 this or other districts. But with the vastly more numerous mud- 

 loving, sedentary, and wholly or semi-parasitic species of Copepoda the 

 case is differen Investigations as to the food of fishes have shown 

 us that even scarce species, and but recently known Copepoda, as in 

 the case of Jonesiella hycence, are found largely in the stomachs of 

 yoiing fishes, being evidently selected by them as theii' chief food, and 

 probably found in quantities near to the spawning grounds. From 

 this aspect even apparently lifeless mud has, under the microscope, 

 much to teach us. In addition to the examination of deposits, it is 

 evident that Sponges, Coelenterates, Echinoderms, "Worms, Molluscs, 

 iS"udibranchs, and Ascidians will richly rewai'd careful search; for, 

 judging from past results, they are the hosts of many highly organized 

 species of Copepoda, each specially adapted to its particular host and 

 sometimes to that alone. 



In conclusion, I would express the hope that we may at a future 

 time be enabled to know as much about the distiibution of the Yalencia 

 sedentary species of Copepoda as we now do of the free-swimmers. 



BrBLIOGBAPHT. 



Beady, Gr. S., and Eobektsox, D. — 1873. " On llarine Copepoda taken 



in the West of Ireland." Ann. and ilag. IS^at. Hist., ser. 4, 



vol. xii. 

 Heediia^-. W. a.— 1891. " The Biological Eesults of the Cruise of the 



S.T. 'Ai'go ' round the West Coast of Ii-eland in August, 1890." 



Trans. Biol. Soc, Livei-pool, vol. v., pp. 181-212. (Contains a 



table, compiled by I. C. Thompson, showing the distribution of 



the Copepoda). 

 llALCOLMSoif, S. II. — 1886. Copepoda. "First Eeport of the Marine 



Fauna of the South-west of Ii-eland." Proc. Roy. Acad., Dublin, 



ser. 3, vol. iv., p. 636. 

 Thompsok-, I. C. — 1896. " Free-swimming Copepoda from the West 



Coast of Ireland." Trans. Biol. Soc, Livei-pool, vol. x., pp. 



92-102. 

 Thompson, I. C. — 1897. "Further Eeport upon the Free-swimming 



Copepoda of the West Coast of Ireland." Trans, Biol. Soc, 



Liverpool, vol. xi., pp. 127-131. 



