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



4. Chonelasma calyx, n. sp. (PI. LXXXIX.). 



In contrast to the above described simple plate-like forms, the species now to be 

 noted, which I have established from three dried and partly macerated specimens 

 obtained by Dr. Doderlein in Enoshima, has the form of a cup several decimeters high, 

 with nipple or glove-finger-like radial protuberances from the wall, which is 5 mm. in 

 thickness. The majority of these parietal protuberances, which have the thickness of one's 

 finger or thumb, exhibit a terminal or subterminal circular aperture from 3 to 5 mm. in 

 diameter, and are continued as thinner tubular or half channeled hollow irregular 

 cyhndrical processes, which either extend obliquely downwards and reach the firm sub- 

 stratum, or unite with the adjoining processes of neighbouring diverticula (PI. LXXXIX. 

 figs. 1, 2). The whole wall is traversed by canals which open alternately on the inner and 

 outer side, but the dried specimens at my disposal do not show the arrangement with 

 equal clearness throughout. 



The dictyonal framework, which consists partly of perfectly smooth beams and partly 

 of beams sparsely covered with tubercles, exhibits a thicker and less regular meshwork in 

 the neighbourhood of the outer and inner bounding surfaces than in the middle layer, 

 where the meshes are large and more uniformly rectangular. The dermal skeleton consists 

 of hexacts, each of which has a terminally corroded, knobbed, and fir-cone-like distal ray 

 which is beset with pointed prongs, while the long conical proximal ray, and the four 

 moderately long transversals, are either quite smooth or beset on their outer extremities 

 with small tubercles. In addition to the hexacts, the very numerous radially projecting 

 scopulge usually bear six, more rarely five or four, barbed, more or less markedly diverging, 

 knobbed terminal rays, or a cap-like swelling on the shaft which terminates in a rough 

 point (PI. LXXXIX. fig. 6). The spicules of the gastral skeleton exhibit a similar 

 structure, but the freely projecting (proximal) ray of the hexacts is often somewhat more 

 slender than in the dermal hexacts. The scopulse, moreover, vary considerably in the 

 number of their barbed and usually markedly knobbed terminal rays. 



The parenchymal uncinates are remarkable for their strength. The greatest swelling 

 always occurs in the anterior third dermal portion. Among the smaller loose parenchy- 

 malia numerous discohexasters and oxyhexasters must be noted. The number of the 

 moderately/ long terminal rays varies, as has already been described and figured in 

 Chonelasma lamella. The same small discohexacts appear as in the above. 



Chonelasma sp. (PL XC. figs. 8-11). 



Besides the largest specimens figured in PI. LXXXVII. figs. 1 and 2, fragments of 

 macerated dictyonal framework belonging to a Chonelasma form were found at various 

 stations on the Challenger Expedition. I have not been aljle to refer these with any 



