COSMARICM. 191 



drains of the east of England. It is readily distinguished by 

 the form of the cell alone, but the granulation, and especially 

 the binate central tumours, are also characteristic features. 



Lundell was the first to discover the binate central tumours, 

 which Brebisson had described as single. This led to the 

 naming of the form figured by Lundell from Sweden as " var. 

 Lundellii Grutw." It was very soon found that the common 

 European form invariably possessed binate tumours, and an 

 examination by ISTordstedt of Brebisson's original specimens 

 proved them to be identical in all respects with LundelPs 

 Swedish form. Brebisson's description and figure of (7. 

 Turpinii are thus very inaccurate, and G-utwiiiskr's " var. 

 Lundellii" is nothing' more than the typical plant. 



As previously stated in vol. ii, p. 68, Borge has suggested 

 that Euastrum occidentale W. & Gr. S. West is very probably 

 a form of C. Turpinii. This we do not admit, and compared 

 with the latter, the former is an exceedingly rare Desmid. A 

 careful comparison should be made between fig. 20, PI. 

 XXXIX and fig. 16, PI. LXXXII. The semicells are unlike 

 in form, and both the granulation and the central tumours 

 are of a different character. 



Var. podolicum Gutw. (PI. LXXXIII, fig. 2.) 



C. Turpinii var. podolicum Gntw. Walir. d. Prioritat, 1890, p. 71 ; Flor. 

 Grlon. Okolic Lwowa, p. 62, t. 3, f . 2 ; Johnson, Eare Desm. U. S. II, 

 p. 294, t. 240, f. 18; Schmidle, Beitr. Algenfl. des Schwarzwald. u. 

 Oberrheins VI, 1897, p. 23, t. 2, f. 10-11 [figures very poor]. 



Cells very variable in size, sometimes rather wider 

 than in the type ; semicells with 2-3 emarginate (or 

 bigranulate) crenations at each side just below the 

 apex, with a row of 6 or 7 granules just above the 

 isthmus, apex retuse with either a smooth or granulate 

 margin ; granules on various parts of the cell- wall often 

 pfeminate. 



o 



Zygospore globose, covered with large mamillate 

 warts, each of which is terminated by a short, stout, 

 truncate spine. 



Length 46-84 /u ; breadth 40-83 /u ; breadth of isth- 

 mus 12-21jLt; thickness 26-43^; diam. zygosp. with- 

 out spines 54 /it, with spines 68 ^. 



IRELAND. Plankton of Louo-h Xeaoii and Louo-h 



O O O 



Beg! 



