STAURASTRUM. 145 



A variety with very short processes, which are less 

 than half the normal length ; arrangement of verrucse 

 as in the type. 



Length 53-65 JJL ; breadth, with processes, 72-88 a. 



ENGLAND. --In the plankton of Ennerdale Water, 

 Cumberland ! : and Easedale Tarn. Westmoreland ! 



J s 



Geogr. Distribution .--^OTWB,J. Finmark. 



This variety, although not exclusively confined to plankton, 

 prefers this habitat to any other situation. 



Var. biradiatum West, (PL CXLVII, fig. 2.) 



N/. 'iiififlninn subsp. biradiatuni \\Vst, Al<r. W. Ireland, 1892, p. 185, t. 24, 

 f. 3. 



Cells slightly smaller than in the type, about twice 

 as broad as long, including the processes, deeply con- 

 stricted. sinus nearly linear for part of its length, semi- 

 cells subfusiform, ventral margin much more convex 

 than the dorsal, processes not so divergent as in the 

 type. Vertical view fusiform, produced into processes 

 at the poles, lateral margins verrucose, with a series of 

 verruca? just within each margin. 



Length 40 \L ; breadth, with processes, 82 [j. : breadth 

 of isthmus 8 \L ; thickness 23 ^ . 



IRELAND.- -Lakes, near Recess, Galway ! Adrigole, 

 Cork! 



Var. truncatum West. (PL CXLVI, fig. 8.) 



<s7. (uirttinum var. truncafiim West, Alg. W. Ireland, 1892, p. 185, t. 24, 

 f. 2 ; West & G. S. West, Further Contrib. Plankt. Scott. Lochs, 1905, 

 p. 486. 



Semicells more elliptical than in the type, ventral and 

 dorsal margins almost equally convex, but with the apex 

 distinctly flattened, processes inserted lower than in the 

 type, and beginning abruptly, the " body ; ' not tapering 

 so gently into the processes. 



Length 50-65 (JL ; breadth, including processes, 75- 

 100 \JL ; breadth of isthmus 15-20 p. 



SCOTLAND.- -Plankton of Lochs Cuthaig, Fadaghoda, 



VOL. v. 10 



