NORTH AMERICAN PLANKTON. 75 



It has already been recorded from Minnesota (U.S. A), by 

 C. L. Herrick, in his report on the Cyclopidae of Minnesota, 

 so that it would appear to be a widely distributed species. 

 On the Continent of Europe, E. affinis sometimes occurs 

 in immense profusion, constituting, it is said, at some 

 seasons, the almost exclusive food of certain fishes, as of 

 the Shad in the Rhine and the Herring in the Baltic. 



A striking new species of Eurytemora, which is des- 

 cribed and figured below as E. lierdmani, was found in fair 

 numbers in some gatherings in the St. Lawrence. 



Pleuromma abdominale occurred plentifully, particularly 

 amongst the plankton collected towards the other side, 

 and in Mid- Atlantic, though sparingly taken in British 

 waters. The distinguishing generic character, the dark 

 coloured pleural eye, though generally present, was cer- 

 tainly entirely absent in many specimens, those with and 

 those without the eye being found in the same gathering. 

 Brady refers to the absence of the eye in many specimens. 

 The nearly allied form, Metridia armata, was found 

 generally distributed towards this side of the ocean. It 

 is generally a very noticeable feature in plankton collec- 

 tions taken off the west Irish coast. 



HeterocJiceta spinifrons was found very sparingly in 

 collections taken between mid-ocean and Canada. The 

 collection shows an extension of the distribution of this 

 species in the North Atlantic. 



Candace pectinata only occurred in a single gathering, 

 the one taken between Bockall and the north coast of 

 Ireland. North of the Mediterranean this species does 

 not appear to have been taken anywhere else except 

 round the British coasts, in several parts of which it has 

 been recorded since Brady first described it from speci- 

 mens collected at the Scilly Islands. 



Labidocera icollastoiii occurred in the collections made 



