30 R- Gronblad, New Desmids. 



constrictae. Semicellulae subsemicirculares-subtrapeziformes 

 angulis basalibus valde rotundatis, lateribus convexis con- 

 vergentibus, angulis superioribus non rotundatis, apice late 

 truncato, marginibus omnibus levissime crispulis. Membrana 

 granulis parvis sparsim obsessa, sed circa aream centralem 

 plane glabra; utrimque supra isthmum granula nonnulla 

 (2 — 5), itemque in area centrali (circ. 5) conspiciuntur. A 

 vertice visum oblongum medio utrimque non vel vix sub- 

 tumidum, summa apice glabro. Massa chlorophyllacea axilis 

 in utraque semicellula nucleis amylaceis binis et laminis 8 

 radiatim exeuntibus. Long. 44 — 46, lat. 38 — 40, crass. 25, 

 isthm. 12— 14//, [N:o 1174]. 



Nearest to C. botrytis Menegh., from which it is dis- 

 tinguished by the broadly truncate apex, more depressed 

 semicells, more rounded lower angles and more convex 

 sides, as well as the delicate and sparse granulation. 



Hab. In a basin, Botan. Garden, Helsingfors (S). 

 PI. 6 fig. 18—19. 



var. subetchachanense nova var. Marginibus plus crispis 

 (apice glabro), membrana granulis densius obsessa, area 

 glabra circumcentrali nulla; cellulis a vertice visis plus regu- 

 lariter ellipticis. Massa chlorophyllacea ut in typo. Long. 

 48, lat. 39, crass. 25, isthm. 11 //. [N:o 991]. 



This variety should be compared with C. etchachanense 

 Roy & Biss. (West, Mngr. Ill pi. 81 f. 1) and with C. 

 botrytis. Formerly I would have united both the type and 

 the variety merely as varieties of C. botrytis (Compare f. 

 ex. var. depressum West, Mngr. IV pi. 97 f. 6). But the 

 outline of the cells and the nature of the granulation are 

 very different. — Here I would remark that, in my opinion, 

 var. mediolaeve West, Mngr. IV pi. 97 f. 5 and var. meso- 

 leium Nordst., Desm. Ital. pi. 12 f. 2 are not forms of 

 C. botrytis and should be relegated elsewhere. They belong 

 to that group of Cosmaria which has the granules arranged 

 concentrically and radially. 



Hab. Near Helsingfors (S), leg. Elfv. PI. 6 fig. 



20—21, 30. 



