REPORT ON THE HEXACTINELLIDA. 397 



surface, covered only by the sieve-like Ijounding membrane, but end in a blind point at 

 the other extremity. They thus always correspond approximately in length to the 

 parietal thickness of the sponge. 



Single Genus Chonelasma, n. gen. 



The body consists of an upright plain or slightly curved plate about the size of a hand, 

 and exhibiting an irregularly chambered smooth free margin, or of a funnel-shaped cup 

 with lateral glove-finger-like parietal diverticula. 



Species 1. Clionelasma lamella, n. sp. 



The dictyonal framework enclosing rectangular meshes exhibits in its median region 

 a loose structure with wider meshes than in the neighbourhood of the two bounding 

 surfaces. The beams of the framework are usually beset with small pointed tubercles, 

 and are connected without thickening of the nodes of intersection. The parenchyma 

 includes, besides the uncinates and simple rough minute oxyhexacts, small rough disco- 

 hexacts, oxyhexasters, and discohexasters with long terminal rays. 



The dermalia and gastralia are strongly developed pentacts, in which the proximal or 

 distal radial ray, as also the sides of the four tangentials turned towards the free surface, 

 are richly beset with short spines. Besides these the dermal skeleton contains scopulse, 

 with four knobbed, straight prongs, which rise from a thick stalk-node. Kermadec 

 Islands, 520 fathoms; west of Kerguelen Islands, 550 fathoms; Bermuda Islands, 

 1705 fathoms. 



Species 2. Chonelasma hamatum, n. sp. 



An upright, hand-shaped plate, 3 to 5 mm. in thickness, with a slightly undulating 

 curvature, and with irregular roundish marginal contour. The dictyonal framework 

 resembles that of Chonelasma lamella. The loose parenchymalia include, besides uncinates 

 and numerous small rough oxyhexacts which tend to become soldered to the dictyonal 

 framework, small discohexasters, some of which bear short principal rays -n-ith six to eight 

 long, S-shaped terminals in perianth-like arrangement, while others possess long, rough, 

 strongly developed principals, with short, S-shaped terminals. The dermal and gastral 

 skeleton is formed of hexacts, in which the projecting radial ray is short and beset with 

 inconspicuous spines. Besides these the dermal skeleton especiaU}^ contains abundant 

 scopulse, some of which bear near the outer end of their stalk an annular swelling or four 

 cruciately disposed bosses, in which an intersection of axial canals can be distinctly seen. 

 Their four straight or slightly S-shaped prongs end cither in a simple rounded off 

 extremity, or in a minute knob-like thickening. Kermadec Islands, 520 fathoms. 



