201 



REPORT on the COPEPODA of the L. M. B. C. 



DISTRICT. 



By Isaac C. Thompson, F.R.M.S. 



The Copepoda reported upon were collected during the 

 summer of 1885, between May and August inclusive. 

 Many of them were captured during the cruise of the 

 " Hyaena" and on the second Hilbre expedition, and a large 

 number later in the season, off Port Erin, at the south end 

 of the Isle of Man. 



It is a remarkable fact that with special opportunities for 

 dredging and tow-netting off Penmaenmawr during July, 

 scarcely any Copepoda were found. Their absence at that 

 time may probably be accounted for by the wide-spread 

 diffusion throughout the sea of the minute gelatinous 

 spherical bodies referred to in the Report on the Fauna of 

 Penmaenmawr. ^^^ 



In this connection it is interesting to fiud that Mr. 

 Pearcey observed, t while conducting tow-netting investiga- 

 tions in the Shetland Seas in the summer of 1884, that in 

 regions -where the diatom Rhizosolenia shruhsolei was pre- 

 sent in great abundance animal life was almost entirely 

 absent in the surface waters. 



The strained material from water containing the specimens 

 captured by the tow-net was treated in two different ways for 

 preservation. Firstly, by hardening with a saturated solution 

 of Picric Acid and then with Alcohol ; and, secondly, by pre- 

 serving in a mixture of Glycerine, Alcohol and Water. The 

 former method, though admirable as a preservative of the 



* See farther on in this Volume. 



t " Movements and Food of the Herring," &c., Proc. Boy. Physical Soc, 

 Edin., vol. viii, p. 389, 1885. 



