SUEFACE AND DEEP TOW-NETTING. 159 



amount of plankton in each tow-net, Galanus finmarchicus 

 was far more abundant at the bottom than at the surface, 

 the preponderance of males being very marked. Pseudo- 

 calanus elongatus was very abundant in both tow-nets, the 

 number of specimens in the lower one being equal to that 

 of all the other species put together. 



Acartia clausii and Oitliona spinifrons were in about 

 equal proportions ; more plentiful in the surface net than 

 in the bottom net, but few specimens of Oitliona being 

 found in the latter. 



Four species of Copepoda were found in the surface 

 tow-net only, viz., Temora longicomis, Gentropages hama- 

 tus, Longipedia coronata, and Euterpe acutifrons. The 

 two first-named are very common British species, being 

 rarely found at any distance below the surface. 



Longipedia coronata is also common, though usually 

 found in rocky pools attached to fuci, between tidal limits. 

 The occurrence of Euterpe acutifrons in considerable 

 quantity is rather surprising, inasmuch as it is a rare 

 species round our coasts, and seldom found in any quantity. 



It is of wide distribution, extending from South America, 

 into the Atlantic, the Canary Islands, throughout the 

 Mediterranean, the northern coasts of France, and at 

 Heligoland. 



Three free-swimming species, not occurring in the sur- 

 face tow-net, were found in the bottom net, viz., Bradyi- 

 dius armatus, Metridia longa, and Gandace pectinata, the 

 latter being entirely new to the L.M.B.C. district, and 

 the two former seldom met with. 



Bradyidius armatus I have found on two or there 

 previous occasions at similar depths. It is readily dis- 

 tinguished from the common Pseudocalanus elongatus, 

 from which genus Giesbrecht has lately removed it, by the 

 strong spinous terminations to the cephalothorax. 



