COSMARIUM. 23 



of C. Quadrum var. minus. Borge records Australian speci- 

 mens np to a length and breadth of 45'5 /.*. 



Another closely allied species is C. creperum W. & Gr. S. 

 West (< Alg. Madag/ 1895, p. 63, t. 7, f. 11), which differs in 

 the open sinus, the more rounded sides of the semicells, and 

 the more distantly arranged granules. 



The granulation of C. Pseudobruomei appears to be variable 

 in density, some specimens exhibiting many more granules 

 per semicell than others. 



Var. convexum W. & G. S. West, (PL C, fig. 9.) 



0. Pseudobroomei var. convexum W. & G- S. West, Freshw. Algae Orkneys 

 and Shetlands, 1905, p. 21, t. 1, f. 22. 



Lateral margins of semicells convex and with, the 

 angles more rounded; grannies as in the type but 

 disposed most evidently in vertical series. 



Length 46 JLC; breadth 37"5 ft; breadth of isthmus 

 12*5 ju, ; thickness 24 /x. 



SCOTLAND. Near Lerwick, Shetlands! 



This variety is slightly larger than any other known form 

 of the species, and is proportionately less wide. 



234. Cosmarium Subbroomei Schmidle. 



(PL C, fig. 10.) 



Cosmarium Subbroomei Schmidle, Beitr. Algenfl. Schwarzwald. u. Rheineb. 

 1893, p. 104, t. 5, f. 22-24. 



Cells small, about as long as broad, very deeply 

 constricted, sinus narrowly linear with a very slightly 

 dilated apex ; semicells oblong-rectangular with slightly 

 rounded angles, sides and apex very slightly convex. 

 Cell-wall finely granulate ; granules about the size of 

 those of C. punctulatum, disposed in 10-12 subvertical 

 series, 25-27 showing at the margin of a semicell, 

 with a few indistinctly arranged granules just above 

 the isthmus in the centre of the semicell. Side view 

 of semicell subcircular. Vertical view rather narrowly 

 elliptical, with three prominent papilla-like granules 

 at the middle on each side. Chloroplasts axile, with 

 two pyrenoids in each semicell. 



Zygospore unknown. 



