the TroniJhjpin Fiord, 111) 



the pinna runs side by sidi; with [)iuna B, the cells touchiiiL^ 

 thiKsi" of B on the ri<;ht; on the left and free side every cell 

 ;L,Mves origin to a pinnula. Pinna B, 1-3, 4 (1), G-12 (2) ; 

 now it comes into contact with pinnaj A and C, and passes 

 between them, the three running side by side from 1-3-17; 

 liere pinna lias diverged to the right, but A is still to the 

 left, so one side only is free and we have 18-29 (1) . Pinna C, 

 1-5, ()-9 (1), 10, 11 ; here it is running along the side of B, 

 which is on its left, so that on that side it cannot branch, and 

 we have 12-18 (1); here it diverges from B to the right, 

 and, being free, we have 19-29 (2), and then a terminating 

 crecj)ing base equal in length to six cells, on which the cells 

 are imperfectly or as yet not at all developed. The zooecia are 

 elongated both in the posterior calcareous portion and in the 

 long and often nearly oblong area; the lateral spines are 

 4 or 6, rarely 8, the posterior spine is no larger than the 

 others * ; the branches diverge from what may be called the 

 shoulders of the zocjccium. In every case where a branch is 

 not given otf to right or left it is from want of room ; the 

 animal seems to discover by its tentacles that there is a 

 neighbour too near to enable itself to develop a zoojcium in 

 that direction : but the direct onward growth of the main 

 stem, pinna, or pinnula is not so easily stopped ; it will run 

 up close to the side of a neighbour and accompany it in its 

 onward course (see Smitt's ligure), or it will ride over its 

 back, if at an angle, and pursue its journey. The pure white 

 lace Avhich this variety forms is a beautiful object seen 

 against the black background of the Fucus on which it is 

 developed. My specimens are from Floro, and it is not 

 unlikely that those of Sars, which Smitt describes, were from 

 the same locality, the fauna of which Sars knew so well. 



Section II. Free-living forms. 



Var. 6. carhasiiformis (PL VII. tig. 2). — Imagine the form 

 s/e//«to, Thompson, living absolutely free, consisting of a lamina 

 composed of a single layer of zooscia, witii calcareous back, 

 and you have this variety. The specimen is 20 millim. in its 

 greater and 16 millim. in its lesser diameter, the outline very 

 stellate ; the area of the zooecia has four, rarely six, or even 

 eight spines on the margin, the posterior spine a little larger 

 than the others. I can see no sign of attachment even at 

 the '' mother-cell." ilodberg, Troudhjem Fiord, 1893. 



* It was so in Suiitt's specimen, and, of course, there may be this 

 variation. 



