COSMAEIUM. 40 



Forma crispula Nordst. (PI. LXYI, fig. I?A.) 



Cosmarium anceps Lund, forma Xordst. Xorges Desm. 1873, p. 2i. 

 C. anceps forma crispula Xordst. Desm. Arctose, 1875, p. 38. 



C. tetragonum (Xiig.) Arch. var. pumilum West & Gr. S. West, Xew Brit. 

 Freshw. Alg. 1894, p. 5, t. 1, f. 19. 



Dysphinctium piirrv.lnm (Breb.) Schmidle var. urul vlatum Schmidl>. 

 Beitr. alp. Alg. 1S95, p. 34S, t. 15, f. 7 'ride Xordst. Index Desmi-1. 

 1S96, pp. 44 and 197 ; West & G-. S. Western Joiirn. Bot. Sept. l.s'.i^. 



D. anceps forma crispula in. Grutw. Xonn. Alg. Xov. 1896, p. 44, t. 7, f. 36. 

 Cosmarium parrulum Breb. var. pumilum West & Gr. S. West, Alga-fi. 



Yorks. 1900, p. 95. 



Generally smaller than typical C. anceps, with the 

 basal anoies of the semicells obscurely subrectanerular 



/ o 



and the sides sligrhtly undulate (one median crest and 



O t/ 



two hollows). 



Length 22'5-88/x; breadth 12-5-20 //, ; breadth of 

 isthmus 7 '5-1 2 p.. 



ENGLAND.- -Near Ilkley, W. Yorks ! 



SCOTLAND. Craig-an-Lochan, Perthshire ! 



o 



Geogr. Distribution. Tyrol. Norway. NovaZembla. 



The exact relationship of this form has been a matter of 

 considerable doubt. We are now of the opinion that it is 

 more nearly allied to C. anceps than to C. parvulum or 

 C. tetragonum. 



Sehmidle has stated (" Znr Kritik einiger Siisswasseralgen," 

 'Nova Xotarisia/ 1897, p. 70) that C. doll forme West & Gr. S. 

 West (< Some X. Amer. Desm./ 1896, p. 246, t. 15, f. 16) is 

 only a form of his " Dysphinc.tium parvulum var. undulatum," 

 but this is not so, as C. doliforme is more nearly related to C. 

 pseudopyramidatum Lund, than to any other Desmid. 



76. Cosmarium obliquum Nordst. 

 (PI. LXIX, figs. 18-21.) 



Cosmarium obliquum Norclst. Norg'es Desm. 1873, p. 23, t. 1, f. 8 [forma 

 minor, forma media, forma major'] ; Cooke, Brit. Desm. 1886, p. 94, t. 43. 

 f . 5 ; Xordst. Freshw. Alg. X. Zeal. 1888, pp. 57, 80 ; De Toni, Syll. Alg. 

 1889, p. 959; West, Alg. X. Yorks. 1889, p. 292; Heimerl, Desm. alp. 

 1891, p. 600; West, Alg. W. Ireland, 1892, p. 149; Alg. Engl. Lake 

 Distr. 1892, p. 726 ; Ltitkem. Desm. Attersees, 1893, p. 548 ; Roy & Biss. 

 Scott, Desm. 1894, p. 169 ; Xordst, In,dex Desm. 1896, p. 184 ; We>t ,V 

 G. S. West, Alg. S. England, 1897, p. 487 ; Alga-fl. Yorks. 1900, p. 91 ; 

 Freshw. Alg. Orkneys and Shetlands, 1905, p. 22. 



Nothocosmarium obliquum (Xordst.) Racib. Desm. Xowe, 1889, p. 98, t. 6, 

 f. 13. 



Ursinella obliqua Kuntze, Revis. gen. plant. 1891, p. 925. 



VOL. III. 4 



