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



Mediterranean species Clavularia crassa to Cornidaria, although the wall of the calyx 

 is furnished with spicules. 



The following three species of this genus occurred in the Challenger collection : — 



A. Stolonifera. 



Clavularia tubaria, n. sp. (PI. XLII. fig. 10). 



The flattened stolons are connected in a reticulate manner. The calyces of the 

 polyps are widely separated from one another. They grow to a height of 17 mm., 

 and are ribbed throughout their entire length. They are narrow at the base and 

 gradually broaden out above. The spicules are thick rough spindles, covered with 

 tubercular warts and warty clubs. The colony surrounds the dead stock of Lophohelia 

 Candida. The stolons are 0'8 to r2 mm. in breadth, somewhat flattened and some- 

 times broader than the base of the polyps which spring from them. They form an 

 irregular wide meshwork, in which the stolons lie at angles of 45° to 90° to one 

 another, leaving triangular or four-cornered interspaces. The polyps originate at the 

 points of intersection or on the ends of simple stoloniferous processes, or more 

 commonly the polyps which spring from the stolons give oflf on two or three sides new 

 stolons which unite with the processes from other polyps. The calyces are rigid, and 

 rise (with a basal thickness of 1 mm.) to a height of 14-5, 16 to 17 mm. They 

 gradually increase in breadth, and attain at the oral extremity a diameter of 2 mm. 

 Their longitudinal axis is seldom straight, usually slightly bent, and often exhibits a 

 slight sigmoid upturned curvature. 



Eight deep radial furrows extend from the oral region to the base of the calyx, where 

 they become obliterated. Between these the calyx wall projects in eight longitudinal 

 ridges, which reach to the calycine margin, and there pass down the opening of the calyx 

 into the indrawn tentacular portion, coming together in such a way that the calyx seems 

 to be closed by an eight-rayed star. The retractile portion of the polyp includes the 

 oesophageal portion, the oral disc, and the bases of the tentacles. In all the polyps it was 

 drawn in into the interior of the calyx, so that the bases of the tentacles were found sunk 

 in the invaginated oesophageal portion, while the tentacles themselves lay folded together 

 over the oral disc. The spicules of the calyx wall are thick warty spindles and clubs, 

 which are closely packed together in the ribbed portion, three or four in a row. Thus 

 the calyx has a rigid character. Among the spicules one can distinguish thick clubs closely 

 beset with spiny warts (0-28 mm. or 0-32 mm. in length and 0-16 mm. or 0-13 mm. 

 in diameter at the thicker end), spindles with rounded ends, straight or slightly curved, 

 and beset with broad spiny warts, in length and breadth 0-33 and 0-067 mm., or 0-4 and 

 0-041 mm., or O'lB and 0-07 mm. The largest and thickest spicules lie in the middle 



