FRESH-WATEll dCLOPIDiE AND CALANIDiE. 41 



of the right fifth foot in the male not dilated at the base. Pen- 

 ultimate joint of the fifth foot in the female twice as long as 

 the preceding joint, armed with one spine only on its outer 

 margin, its inner margin produced towards the apex so as to form 

 a large dagger-like spine, the base of this spine extending over 

 less than one half of the margin of the joint. Length of the 

 female 1*8 mm. 



This species occurs commonly in salt-marsh pools and estuaries, 

 and sometimes in fresh water. It has been recorded from the 

 Neva, near Peterhof {Fischer) ; the Baltic {Lilljelorg) ; Finland, 

 in brackish and fresh water {JVordquist) ; Bremen {Rehberg) ; 

 Leyden {Hoeh) ; N.W. Germany, frequent in fresh-water {Poppe) ; 

 Abbeville, fresh-water, and Croisic, brackish {De Gueme and 

 Richard). 



In Britain I have notes of its occurrences as follows : — In 

 salt-marshes at Hylton (county Durham), Seaton Sluice and 

 Alnmouth (Northumberland), Cumbrae (Firth of Clyde), Pen- 

 sarn (Merionethshire), in several of the broads of Norfolk and 

 Suffolk ; Whittlesea Dyke, Cambridgeshire ; and in pools near 

 the river Stour at Manningtree {G.S.B.) ; Higham Park, Essex, 

 fresh-water {Mr. D. J. Scour field !). In brackish pools fully 

 exposed to the rays of the sun it seems to luxuriate, often fairly 

 swarming in such places. The few specimens which I have 

 recorded as being taken in the sea at Sunderland, must, I think, 

 be looked upon as waifs and strays. 



It seems to be taken for certain by some authors (Poppe, De 

 Guerne & Kichard) that Prof. Lilljeborg's original description 

 of Temora velox must have been drawn up from the male of T. 

 affinis and the female of T. Clausii; and no doubt the drawings 

 given by him of the fifth pair of feet in the two sexes go to 

 support this view. But the characters of these organs seem to 

 be, to a certain extent, inconstant. In a gathering, for instance, 

 of T. affinis, from Falmouth, there occur many examples of males 

 which are without the characteristic dilatation of the claw of 

 the fifth foot, while the fifth feet of the females from the same 

 place have the characters of typical T. affinis. And, again, the 

 drawing with which I myself illustrated T. velox in the North- 



106 



