214 BRITISH DESMID1ACEJE. 



two prominent grannies (transversely disposed) in the 

 centre of the semicells. Side view of semicell circular, 

 with a grannie rather below the middle on each side. 

 Vertical view elliptic or elliptic-oblong, with a pair of 

 prominent grannies (almost forming a slight bigrann- 

 late tumour) at the middle on each side, in the centre 

 with an elliptical smooth area. Chloroplasts axile, 

 with one central pyrenoid. 



Zygospore unknown. 



Length 20 /x; breadth 19 p. ; breadth of isthmus 7/x; 

 thickness 11 '5 /x. 



WALES.- -Capel Cnrig and Yr Orsedd, Carnarvon- 

 shire ! 



IRELAND. Near Westport, Mayo ! 



Geocjr. Distribution. Brazil. 



This species appears to be distinct from C. punctulatum by 

 reason of its less numerous granules and the bigranulate 

 central area of the semicells. It is also considerably smaller. 



Forma subrectangularis /. nov. (PI. LXXXV, fig. 7.) 



Semicells snbrectangnlar, apical angles rather more 

 rounded than the basal angles ; granulation as in the 

 type. 



Length 24 /x ; breadth 21 ^; breadth of isthmus 6 /*; 

 thickness 13 JJL. 



SCOTLAND.- -Harris, Outer Hebrides ! 



The Desmid described and figured by Eaciborski (in 

 ' Spraw. Kom. Fizyj. Akad. Umiej. Krakow/ xix, 1884, p. 12 

 (sep.), t. 1, f. 4) as C. polonicum appears to be intermediate 

 in character between C . punctulatum and C. lApunctatum, but 

 Raciborskr's " species " requires accurate investigation. 



191. Cosmarium bipapillatum West & Gr. S. West. 



(PI. LXXXV, fig. 8.) 



Cosmariiim Boeckii Wille subsp. bipapillatum West, Alg. W. Ireland, 



1892, p. 157, t. 21, f. 14 ; Xorclst. Index Desm. 1896, p. 63. 

 C. bipapillatum West & G. S. West, Xew Brit. Freslnv. Alg. 1894, p. 7. 



