STAURASTRUM. 191 



but rounded mucro. Vertical view triangular, with 

 straight sides and slightly rounded angles, each ang'le- 



^^ CT5 / 



furnished with a rather blunt mucro. Cell-wall 

 granulate, granules rather distant, those near the angles 

 more or less papilliform and arranged in three con- 

 centric series, granules away from the angles much 

 smaller, irregularly punctate between the granules,. 

 apices of semicells smooth. 



Zygospore unknown. 



Length 36*5-40 //,; breadth with macros 32-38'5 //,;. 

 breadth of isthmus 12* 5-1 3*5 //,. 



ENGLAND.- -Pilmoor, IN". Yorks ! "\Vicken Fen, Cam- 

 bridge ! 



This species should be compared with St. granulosum 

 (Ehrenb.) R alt's, with which it appears to have a very close 

 affinity. It should also be compared with St. brdchyacanthum 

 Nordst. 



41. Staurastrum inflatum sp. nov. 

 (PI. CXXVII, fig. 23.) 



Staurastrum Kjellmani Wille var. rotundatum W. & G. S. West, New and 

 Int. Freshw. Alg. 1896, p. 158, t. 4, f. 46; Alga-fl. Yorks. 1901, p. 102 

 ["rotundum"]. 



Cells rather small, about If longer than broad, 

 moderately constricted, sinus very widely open and 

 obtuse-angled; semicells obovate-subcircular, the widest 

 part being about two-thirds the height of the semi- 

 cell. Vertical view quadrate-circular. Cell- wall 

 densely granulate ; granules fairly large with no defi- 

 nite disposition, a little smaller towards the isthmus. 



Z y go spore unkn own. 



Length 43 JJL ; breadth 25-26*5 //, ; breadth of isthmus. 

 13'5 //,. 



Hab.Ogden Clough, AY. Yorks ! 



This species is at once distinguished from St. punctulatum 

 var. Kjellmani by its proportionately greater length, its more 

 open sinus, its much more rounded semicells, and its coarser 

 granulation. 



The name " rotundatum ' is already in use for an Indian 

 species of this genus. 



