230 • THE VOYAGE OF H.M.S. CHALLENGEE. 



The stem and branches are stout, fragile, and quite inflexible ; their surface has a 

 rouo-h granular character. The scattered polyps cause them to appear as though covered 

 with warts. Even the terminal twigs do not show the cluster-like form found in the 

 preceding genus, for the polyps everywhere project stifily from the base, and are 

 distinctly separated from one another. The canals in the stem are very numerous, and 

 very irregular, being angular or oval, or slit-like in section. Their diameter varies 

 from 2 to 0'8 mm. The partition walls which divide them increase in thickness from 

 the outside towards the inside, attaining as much as 1 mm. in diameter. In the axis of 

 the stem these partition walls unite together to form a central portion, which is very 

 irregular in section. In the branches the canals are relatively wider and less numerous ; 

 there are eight in a slender branch, 4 mm. in diameter ; they are radially arranged and 

 still contain mesenterial folds on which ova are developed. 



The spicules are warty spindles, sometimes thickened at one end, frequently simply 

 curved ory^shaped, surrounded by blunt, vertical warts. 



In the calyces large y^shaped spindles are arranged in obliquely ascending rows, in 

 such a manner that one spicule frequently extends half round the wall. At the base of 

 the tentacles they are peripherally disposed and form a kind of collaret. In the bases 

 of the tentacles, which when folded together cover the oral region forming a kind of 

 operculum, small, spiny, somewhat flattened spicules occur, arranged en chevron. Small 

 spicules also occur everywhere between the large spindles, filling u]) the intervals. Size 

 of the spicules — in the branches and twigs ri4 by O'l, 0"5 by 0"05 mm.; in the polyps 

 0"4 by 0'025 mm, 0"54 by 0'08 mm.; in the collaret 0-25 by 0'025 mm.; small spicules 

 0-08 by 0-03 mm.; in the tentacles 0-09 by 0-08 mm. 



Colour in alcohol, brownish-grey. 



Habitat.— ^iSiiiOTi 208, lat. 11° 37' N., long. 123° 31' E.; Philippine Islands; depth, 

 18 fathoms; bottom, blue mud. 



Genus Chironephthya, n. gen. 



Colony rigid, upright, ramified. The ascending barren stem gives off after a longer 

 or shorter course, stifl*, finger-like branches, which either remain simple or give off a few 

 stout secondary branches. The polyps arise at wide intervals along the whole extent of 

 the branches, at the apex they are somewhat more crowded. They consist each of a 

 calyx, which is pressed against the branch, a retractile oesophageal portion, and a 

 tentacular portion which is provided at the base with a collar of spicules. The bases of 

 the tentacles, armed with spicules, form a conical, quasi operculum. 



In the ectoderm of the stem and branches there are a number of large spicules lying 

 close together, and the same applies to the dividing walls of the canal-system, so that the 

 entire colony acquires a rigid brittle consistency. In the slender branches the canals are 



