STAURASTRUM. 83 



Length 27-32 pi ; breadth 26-32 [i ; breadth of isth- 

 mus 7'5-14fji. 



ENGLAND.- -New Forest, Hants ! 



SCOTLAND. Glen Dye, Kincardine (Roy & Biss.). 

 Rhiconich, Sutherland ! 



IRELAND.- -Lough Nacung, Donegal ! Kylemore, Gal- 

 way ! 



Geogr. Distribution.- -France. Sandwich Isles. United 

 States. 



St. subscabrum differs from St. scabnun in its proportionately 

 shorter cells ; the sinus is narrower, and the semicells are more 

 truncate-pyramidate in outline. 



Forma scabrior West. (PL CXL, fig. 5.) 



St. subscabrum forma scabrior West, Alg. W. Ireland, 1892, p. 176, t. 23, 

 f. 4. 



Differs from the type in its greater development of 

 verrucaa, especially at the apices of the cell. 



Length 40 \L ; breadth 35-37 \L ; breadth of isthmus 



10 p. 



IRELAND.- -Kylemore and Clifden, Co. Galway ! 



SECTION H. 



Processes smooth, although usually emarginate, furcate or spinate 

 at the extremity. 



* Processes borne singly at the angles of the semicell. 



f Processes always entire and distinctly capitate at the 



extremity. 



102. St. bacillare. 



ft Processes truncate, obtuse or furcate at the extremity, 



never capitate. 

 Cells minute, semicells rectangular in form. 



103. St. franconicum. 



104. St. inconspicuum. 



105. St. nodosum. 



It Cells larger, semicells cuneate. 



106. St. bmchiatum. 



107. St. Icevispinum. 



108. St. sublcevispimim. 



