lOG THE VOYAGE OF H.M.S. CHALLENGER. 



The coenencliyma and body spicules form a deep layer of long spindles, armed with 

 pointed spines, O'S mm. long by O'OS mm. in diameter, or 0-23 mm. by 0-r2 mm. 

 There are also broad flat spic-ules with simple or branched prominences, which often lie 

 in diflereut planes ; and occasionally some spicules similar in appearance to the " Stachel- 

 platten " met with in Paramuricea. The apices of these often project from the 

 ccenenchyma and give it a roughened spiny appearance. These spicules measure 

 0-2G ; 0"35 ; 0-29 mm. ; with a diameter of 0-06 mm. and more. Small, angular 

 spicules with spiny prominences, which are more especially developed from the 

 angles, have a length of 0"16 mm. The spicules in the tentacles are arranged in two 

 converging series ; they are simple spiny sj)indles of from 0'5 to 0"3 mm. in length. 



The axis is horny, flexible, though brittle when dried as in Paramuricea. The 

 colour of the stem is a dark brow^i, getting lighter towards the termination of the 

 branches. 



The coenenchyma and the polyps are white. 



Habitat. — Station 210, off" the Philippine Islands; depth, 375 fathoms; bottom, 

 blue mud. 



Genus 5. Clematissa,^ n. gen. 



Like Muriceides in its habit, but resembling Paramuricea in its club-like 

 thickened terminal branches, whose apices end in polyps. The spicules of the polyps 

 are spiny, club-like, thickened at one end ; not presenting the regular arrangement 

 of those of Paramuricea. The basal portion of each tentacle, which is not retracted, 

 contains two rows of converging, unilaterally thickened spicules. 



The genus Clematissa shows in its habit a near relationship to Paramuricea. 

 The three species included in it form large colonies branched in one plane, with long 

 terminal branches, which at their apices are thickened and knob-like. 



The coenenchyma is thick, rough, and opaque. The polyps are arranged in short spirals 

 on the stem and its branches ; towards the termination of the branches they are closely 

 crowded, so that they present a knob -like appearance. The termination of a branch is 

 always formed by a polyp. The polyp calyces are bluntly conical, and rise for the most 

 part upright from the stem and its branches. The oesophageal portion of the polyp, 

 which in repose is retracted, is relatively short ; there is always a colleret of spicules, 

 arranged in a ring-form. 



The tentacular portion, which is not folded inwards, is relatively large and armed 

 with large converging spicules, so that the. ..eight basal portions of the tentacles form 

 over the oral region an eight-rayed conically projecting operculum. 



The spicules of the coenenchyma are stout, usually thickened, with a knob-like 

 termination liearing asperities ; sometimes armed with branched spines, sometimes 



^ K'KYjUa.Tioaci. 



