40 BRITISH DESMlDIACiLE. ' 



Bennett/ Alg. N. Cornwall/ 1887, p. 17, t, 4, f. 20, 21 Cooke, 

 'Brit. Desm? 1887, p. 187, t. 65, f. 3; De Toni, < Syll. Alg./ 

 1889, p. 1074 (HeliereUa crenulata Kuntze, 'Kevis. gen. plant./ 

 1891, p. 898) is most probably identical with C. Regnesi var. 

 nunitanum. Bennett's figure (fig. 20) of the front view leaves 

 little doubt of this. His fig. 21 we can only regard as quite 

 erroneous. 



70. Cosmarium cymatonotophorum West. 

 (PI. LXVIII, figs. 37-39.) 



Cosina'rinm cymatonotophorum West, Alg. Engl. Lake Distr. 1892, p. 726, 

 t. 9, f. 23 ; Nordst. Index Desni. 1896, p. 96 ; West & G. S. West, Alg. 

 S. England, 1897, p. -187. 



Cells very small, about as long as broad, fairly 

 deeply constricted, sinus widely open, conical with an 

 obtuse apex ; semicells transversely rectangular, sides 

 subtruncate or slightly retuse, apex broadly truncate 

 (very slightly convex) with four small undulations, all 

 the angles slightly rounded. Side view of semicell 

 subcircular, with a papilla at the middle on each side. 

 Vertical view elliptic, ratio of axes about 1 : 2'3, with a 

 prominent papilla at the middle on each side. Cell- 

 wall smooth. Chloroplast axile, with a central pyrenoid. 



Zygospore unknown. 



Length. 13 '5-14* 5 /A; breadth 13'5-14'5 /x ; breadth 

 of isthmus 5*5-6 p. ; thickness 9*8 /^. 



ENGLAND.- -Hawkshead, Lanes ! Thursley Common, 

 Surrey ! New Forest, Hants ! 



IRELAND. Lakes between Clifden and Rounclstone, 

 Gralway ! 



This minute species is exceedingly rare and appears to be 

 confined to some of the old Sphagnum-bogs, more particularly 

 those which surround boggy springs and which are almost 

 impassable. It appears at tirst sight to closely resemble C. 

 !!t'(/uesi and C. Novae-Semlise, but is easily distinguished 

 from both these species by the greater depth of the constric- 

 tion, the conical form of the sinus, and the form of the 

 semicells. The widely rectangular semicells, with very 

 slightly retuse sides and a 4-undulate apex, are quite 



