108 BRITISH COPEPODA. 



fathoms ; brackish pools near the River Stour, at 

 Manningtree, Suffolk ; abundant on weeds at low 

 water mark, Little Cumbrae; off Portincross, Ayr- 

 shire, fifteen fathoms ; Scilly Islands, ten to forty 

 fathoms; brackish pools at Clifden, Connemara; and 

 in surface-net gatherings from Westport Bay, Mayo. 

 It has also been found by the Rev. A. M. Norman 

 between tide-marks at Oban ; on weeds at Tobermory, 

 Mull ; Bressay Sound, Shetland ; and in brackish 

 water at Isle Oransa, Skye. 



The range of variation of Dactylopus tisboides, especi^ 

 ally as to strength and quantity of setose armature, is 

 very considerable. Two extreme forms, one from 

 brackish water, the other from a purely marine habitat, 

 are figured in the plate, but even in brackish water 

 one may sometimes meet with specimens nearly as 

 strongly spinous and setose as any of those from the 

 open sea. Speaking broadly, however, we may say that 

 there are two races or varieties of the species, charac- 

 terised in one case by a robust body and strong setae, 

 in the other by a slender body and delicate setge. It 

 is interesting to note that, in other species, especially 

 in those whose habitats and consequently whose 

 manner of life are of varied character, structural 

 variations not unlike those of D. tisboides are not 

 unfrequently to be found. 



The following remarks of Dr. Glaus, with reference 

 to a species of a closely allied genus, are of much 

 interest : " The stronger, and, on the average, the 

 larger form of Harpacticus nicceensis has a heavy, 

 strong body ill-bred apparently, inactive, and want- 



