8 BRITISH 



Length 48-60 <u ; breadth 42-50 /n ; breadth of 

 isthmus 15-15*5 /*; thickness 22 /LI. 



SCOTLAND. Plankton of Loch Asta, Shetlands ! 



Geogr. Distribution.- -Germany. Gralicia in Austria 

 (?). E. Africa. 



The Scottish specimens possessed rather smaller apices 

 than those described by Schmidle, but were otherwise pre- 

 cisely similar. 



C. obtusatiim is nearly allied to C. cymatopleurum var. 

 tyrolicum, from which it is distinguished by its somewhat 

 smaller size, its deeper constriction, its truncate apex, and its 

 much thinner cell-wall. In outward appearance it has a 

 certain resemblance to some forms of C. oMliodes, but it is 

 smaller, and the surface-markings are of quite a different 

 character. 



Var. Beanlandii nob. (PI. LXV, fig. 15.) 



Cosmarium subundulatum Wille var. Beanlandii West & G. S. West, New 

 Brit. Freshw. Alg. 1894, p. 7, t. 1, f. 10. 



Cells longer than in the typical form, 1J-1-J times 

 as long as broad, apices subtruncate and sometimes 

 subretuse, margin of semicells with about 18 undula- 

 tions. 



Length 65-85 /n ; breadth 55-59 ^ ; breadth of isth- 

 mus 20*5-22,11; thickness 33 ,u. 



ENGLAND.- -Newsholme, E. Yorks ! 



This variety resembles several of the forms of C. specioswn 

 Lund., but is more deeply constricted than any of them, and 

 has no granules within the margin of the semicells. The cells 

 are also proportionately shorter. Compare with C. speciosum 

 Lund. var. simplex Nordst. (' Desm. Spetsb/ 1872, p. 31, t. 6, 

 f. 12) and C. speciosum var. anxtralianum Nordst. ('Freshw. 

 Alg. N. Zeal/ 1888, p. 79, t, 5, f. 9). 



54. Cosmarium venustum (Breb.) Arch. 

 (PL LXVI, fig. 1-3.) 



Euastrum venustum Breb. Liste Desm. 1856, p. 124, t. 1, f . 3 ; Cooke, Brit. 



Desm. 1886, p. 77, t. 35, f. 11 ; West, Alg. N. Wales, 1890, p. 288. 

 Cosmarium venustum (Breb.) Arch, in Pritch. Infus. 1861, p. 732 ; 



Eabenh. Flor. Europ. Alg. Ill, 1868, p. 164 ; Kirchn. Alg. Schles. 1878, 



