:>.")4 DR MURRAY ON THE DEEP AND SHALLOW- WATER MARINE EAIINA 



^Meliiderma stipitctta, 1 Ridley and Dendy. 

 Stylocordyla 2 stipitctta (Carter). 



Tetracttnelltda : ■ 



*Thenea z delicctta, Sollas. 



Hexactinellida 4 : 



Aulocalyx irregularis, 5 Sclmlze. 

 *JBcdanella pipetta, Schulze. 

 *Bathydorus spinpsus, Schulze. 

 ^Caulophacus latus, 6 Schulze. 



Farrea sp. (?). 

 ~*Holascus Jibulatus, Schulze. 



* ,, polejcevii, Schulze. 

 *Hycdoncma conus, Schulze. 



* „ (Stylocalyx) clavigerum, Schulze. 

 *Mcdacosaccus vastus, Schulze. 

 *Pleorhabdus oviformis, Schulze. 



1 The genus Meliiderma stands in much the same relation to Chondrocladia as does Axoniderma to Cladorhiza, having, 

 like Axoniderma, developed a special spicule for external defensive purposes. The form of the extra spicule is, however, 

 totally different in the two cases ; and in Meliiderma it appears to be confined to the stalk, while in Axoniderma it is 

 most abundant in the body of the sponge. In both these cases it is very difficult to say whether the extra spicule ought 

 to be classed amongst megasclera or microsclera ; for the sake of convenience both will here be regarded as microsclera, 

 though standing on quite a different footing from other microsclera. The form of the extra microsclera in Meliiderma 

 stipitata is as yet unparalleled. From their resemblance to spears or darts we have derived the generic name. . . . 

 Only one perfect specimen of this sponge and one damaged one are in the collection ; in both of these the stalk is 

 encrusted by a thin, yellow, velvet-like layer of the densely packed, spear-like spicules. At first we thought that these 

 .spicules belonged to some foreign encrusting sponge, and hence no mention of them was made in our Preliminary 

 Report, but subsequent examination has convinced us that they are proper to the species ; the fact of their occurring 

 in both specimens being strong evidence in favour of this view. An interesting point about the sponge is the position 

 in which the embryos develop. In the specimen which we cut open a number of round yellow bodies were found, each 

 enclosed in a membranous capsule around which the chelate spicules were lying in very great numbers. These embryos 

 were placed in a zone of tissue occupying about the centre of the spherical head, and lying immediately above the 

 expanded termination of the stalk, between the bands of spiculo-fibre which radiate from it ; this being obviously the 

 position of greatest security. — (Ridley and Dendy, Zool. Chall. Exp., part 59, pp. 102, 103.) 



2 The genus Stylocordyla still stands aloof from all other Suberitidac in its remarkable spiculation, though, as regards 

 external form, the old distinction embodied in the term Stylocordyla no longer holds good, for similar stipitate forms 

 are found to occur in the genus Sidjerites. . . . The external form of this sponge is very variable. Schdlze, as veil 

 as Carter, has already noticed that the head in young forms is more or less round ; we have to notice below a variety in 

 which the head is globular even in the adult. — (Ridley and Dendy, Zool. Chall. Exp., part 59, pp. 222, 223.) 



'■'■ The genus Thvnea is the characteristically deep-water genus of the Tetractinellida, the shallowest water from 

 which it has yet been recorded being 78 fathoms, the deepest 1913 fathoms. — (Sollas, Zool. Chall. Exp., part 63, p. 404.) 



4 It is a striking fact that [among the Hexactinellida] the Asconematidre, which occur somewhat abundantly in 

 the south temperate zone, and likewise in the north, are represented in the tropics only by a single species. — (SCHULZE, 

 Zool. Chall. Exp., I' 111 ' 1 r,: '> 1'- 44 ^) 



6 Aulocalyx irregularis appears to be widely distributed, since it was found both in the north and south temperate 

 zones. — (Schulze, Zool. Chall. Exp., part 53, p. 45C).) 



c Caulopkacus lain* was found in the south temperate zone, the other species, Caulophacus elegans, far removed in 

 the northern regioD.— (SCHULZE, Zool. Chall. Exp., part 53, p. 450.) 



