BRITISH DESMIDIE^. 215 



44. S. pileolatum (Breb.) ; frond quadrilateral, slightly constricted at 

 the middle ; segments terminated by three conical processes. 



Staurastrum pileolatum, Brebisson, in lit. cum icone (1846). 

 Falaise, Brebisson. 



Frond twice as long as broad ; segments quadrate, with a broad, shallow 

 sinus on each side ; the end terminated by three conspicuous conical pro- 

 cesses, which are rough with minute granules. End view triangular, the 

 angles rounded. 



Tab. XXXV. fig. 22. from drawings by M. de Brebisson : c. front view of 

 frond ; b. end view. 



45. S. echinatum (Breb.). 



Staurastrum echinatum, Br^isson, in lit. cum icone (1846). 

 Falaise, Brebisson. 



This species appears, from M. de Brebisson' s drawings, to be closely alhed 

 to Staurastrum hirsutum and S. teliferum. 



Tab. XXXV. fig. 24. from drawings by M. de Brebisson : a. front view of 

 frond ; b. end view. 



46. S. crenatum ; segments cuneate ; outer margins crenate ; 



end view with three truncate and crenate angles. 



Staurastrum, new sp., Bailey, in lit. cum icone (1847). 



Rhode Island, Bailey. 



Tab. XXXV. fig. 17. a. front view of frond; b. end view : from drawings 

 by Professor Bailey. 



47. S. bifidum (Ehr.) ; frond smooth; end view with three cloven 

 angles. 



Desmidium bifidum, Ehr. Abh. der Berlin Ak. 1832, p. 292 ; Infusor. p. 141. 



t. 10. f. 11. 

 Phycastrum bifidum, Kiitzing, Phycologia Germanica, p. 138 (1845). 

 Staurastrum bifidum, Brebisson, in lit. (1846). 



Germany, Ehrenberg . 



48. S, eustephanum (Ehr.) ; end view triangular with six emarginate 

 spines on the upper surface ; each angle terminated by a short ray 

 tipped with spines. 



Desmidium eustephanum, Ehrenberg, Verbr. und Einflxiss des Mikrosk. Lebens 

 in Siid- und Nord-Amerika, t. 4. f. 23 (1843). 



"West Point, New York, Bailey. 



