STAURASTRUM. 105 



does not correspond at all with the description given by Roy & 

 Bissett for the zygospore of the type. It is evident that if both 

 these records be accurate, var. longipes should not be placed as 

 a variety of St. paradoxum, but, because of its very different 

 zygospore, should be considered a distinct species. Whilst 

 further knowledge of the zygospores is to be desired before 

 coming to a definite conclusion, the writer is inclined to the 

 opinion that the zygospore figured by Turner quite possibly did 

 not belong to St. paradoxum var. longipes Nordst. 



Var. cingulum West & G. S. West. (PI. CXLV, 



figs. 9, 10.) 



St. paradoxum var. cinfjulum West & G. S. West, Scott. Freshw. Plankton, I, 

 1903, p. 548, t. 18, f. 6, 7. 



Base of semicell subcylindrical and narrower than 

 in the type, and with a ring of about 12 minute papillae, 

 of which 7 are visible across the base in the front view ; 

 apex of semicell straight or slightly convex ; processes 

 longer and more slender than in the type, gracefully 

 curved upwards. 



Length, without processes, 32-40 p ; including pro- 

 cesses, 71-81 pt ; breadth, without processes, 16-23 [x ; 

 including processes, 64-77 JJL ; breadth at base of semi- 

 cell, 11 '5-1 2 [A ; breadth of isthmus 7*5-8-5 [i. 



ENGLAND. Plankton of Hawes Water, Westmoreland ! 



WALES.- -In the plankton. 



SCOTLAND. Plankton of Lochs Shin and Morar, 

 Sutherland!, Loch Rosque, Ross!, Lochs Katrine and 

 Achray, Perth!, and in the plankton of the Orkneys 

 and Shetlands ! 



IRELAND. Plankton of Loch Currane, Kerry ! 



Geogr. Distribution.- Norway. Australia. 



This variety is exclusively confined to plankton, and is not 

 -at all universal in its distribution. It is distinguished by the 

 narrow cylindrical base of the semicells, furnished with a ring 

 of about a dozen minute spines. The processes are longer than 

 in the typical form and are gracefully curved upwards, 

 body of the semicell is frequently covered with small granules, 

 similar to those on the processes and arranged in concent 

 rings round the base of each process. In length and in curvature 



