THE AMERICAN 



MONTHLY 



MICROSCOPICAL JOURNAL 



Vol. XL JULY, 1890. No. 7. 



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Some Newly-Described Desmids. 



[with one plate.] 



In the June number oi the Journal of the Royal Microscopical So- 

 ciety is a paper by Prof. Wm. West, of the Technical College, Brad- 

 ford, giving a list of fresh -water Algse from North Wales. From it are 

 extracted the descriptions of new species and varieties of desmids, as 

 follows : 



Fig. I. — Gonatozygon i}ii?uitum^\\ON . sp. (G. cellulis subcylindri- 

 cis, apicem versus angustatis, utroque polo constrictis, vicies longius 

 quam latum, cytodermate dense subgraiiulato.) 



About twenty times as long as broad, slightly swollen towards the 

 middle and constricted under the apices, cytoderm densely but slightly 

 granulate. 



Fig. 2. — Des7nldiuin coarctatii?n Nord, var. ca7nbricu7n^ nov. var. 

 (Var. cellulis brevioribus et apicibus latioribus.) 



This chiefly differs from the type in the cells being shorter and hav- 

 ing broader apices. This variety is somewhat doubtfully placed under 

 this species, which it seems to connect with Desmidium cylindricum 

 Grev., the shape of the cells in front view being nearer the latter, but 

 the breadth of the apices bringing it nearer the former. The side view 

 shows the apices to be only about half the thickness of the cells, cor- 

 responding in this respect with D. coarctatuni Nord, with which it 

 also agrees in having the constriction reduced to a mere retuseness in 

 the side view. 



Fig. 3.- — Siaurastruni margaritaceum Meneg., var. coronulatufn 

 nov. var. (Var. ciuii annulogranulorum parvorum ad apices truncatos 

 semicellularum.) 



This has the apices of the semicells truncate and bordered by a circle 

 of small granules. 



Fig. 4. — Siaurastruni bacillare Breb. (Long 17-18 ,a.) 



Copyright, 1890, by C. W. Smiley. 



