BELONGING TO THE GENERA FILIGELLA AND ACIS. V) 



pinnately from the stem or from larger branches at an angle of 

 60-90°. The pinnate arrangement is not always regular in that 

 the branches or the branchlets sometimes arise in nearly opposite 

 pairs and sometimes alternately at intervals of up to one centimeter 

 in length. They are often bent slightly npwards at a short dis- 

 tance from their origin. Both the stem and branches are cylin- 

 drical and rigid, the diameter measuring 2 mm. in the basal part 

 of stem and 1.5 mm. in the terminal parts of final branches. 



The axis is light or dark brown, and is entirely devoid of 

 lime. 



The polyp-cells are disposed all around the cœnenchyma ; 

 only in terminal twigs are they arranged alternately in two rows 

 in the plane of branching. On the tip of twigs there almost 

 always exists a pair of polyps. 



The calyx, into which the distal portion of the polyp can 

 be withdrawn, is low and conical, measuring 0.5-0.8 mm. in height 

 and 1-1.2 mm. in diameter at base. It is formed of scaly spicules 

 arranged in eight longitudinal rows (PI. IL, fig. 13). Usually 

 there are in each row two scales, of which the upper one 

 alone seems to be movable, when the polyp is expanded. The 

 scale is polygonal, dentate in the margin, and often provided with 

 an apical process; the outer surface is covered with small round 

 warts, which in the distal margin are drawn out radially (PI. 

 IL, fig. 14). 



Even when the scales on the margin of calyx are closed, 

 the operculum is usually visible from above. On the dorsal side 

 of tentacles there are two, or rarely three, spicules set close 

 together side by side (PI. IL, fig. 15, b). These are usually 

 unequal in size and slightly bent outwards. The distal extremi- 

 ty of these spicules, when well developed, is rounded but is provid- 



