229 



p. 603, tab. V, fig. 18) and f. depaiiperata Boldt (Dcsm. (Ironi. tab. 2, 

 fig. 35). 



In a gatlierini^, locnlily nol given. 



171. A octocornis Ehrenb. 

 Klakken near Klaksvig (Bord 6). 



172. Xanthidium armatum Bréb. 



Sandsvatn and Grotliiisvaln (Sand 6); KirkcboUanip near Thorsliavn 

 (Sir.); Klakken near Klaksvig (Bord 6). 



173. X. aculeatum Ehrenb. 



Formå supra proniinenliam centralem granulis et aculeis (sem- 

 perV) ornata. Plale VII, lig. 11. 



Long. s. acul. = 67 /< ; lat. s. acul. — 62 fi; crass. — 46 /y. 



Ralfs's figure 1 c of a cell in lateral view (1. c. tab. XIX) shows 

 over the big central protuberances smaller ones and on the empty 

 cell (fig. 1 b) some granules are arranged in a small circle on the 

 lower semicell under the large central protuberance. Generally 

 in the specimens from the Færoes there was a spine directly over 

 these granules, but it was wanting in some specimens. In Ralfs's 

 figure 1 a the upper semicell has such a spine situated also directly 

 over the granules. 



Klakken near Klaksvig (Bordo). 



Formå brevispina. Plate VII, fig. 12. 



Aculeis brevioribus; supra tumorem centralem prominentia 

 minore semilunariiformi prædita; ad .Y. Brébissonii valde accedens. 



Long. s. acul. = 67 /^; lat. s. acul. = 62 /w; crass. = 46 f^. 



By the rather regularly arranged spines on the cell in front 

 view this variety approaches very near to X. Brébissonii. The small 

 oflen crescent-shaped tubercle over the central protuberance is some- 

 times continuous sometimes divided into several smaller granules. 



Kirkebokamp near Tliorshavn (Sir.). 



174. X. fasciculatum Ehrenb. 

 Ralfs 1. c. tab. XIX, fig. 4. 

 Skopen (San do). 



175. X. antilopæum (Bréb.) Kiitz. 



Kirkebokamp (Str.); Skopen, and ralher common in Planklon from 

 Sandsvatn (San do). 



176. X. quadricornutum Roy & Biss. 

 On Scottish Desm. p. 27, tab. IV, fig. 5. 

 Formå longispina n. f. Plate VII, fig. 13. 



