Mr. A. Dendy on a neio Species o/" Claclorhiza. 281 



peculiarity consists in the form of the three teeth at the small 

 end of the spicule. These are elongated, slender, curved , and 

 fang -like ; they are not flattened. They are attached by a 

 rather narrow base to the tubercle and taper gradually to a 

 sharp point at the apex, which is directed towards the large 

 end of the spicule. Their form will be best understood from 

 the illustrations. These spicules measure 0'038 millim. in 

 length and 0*022 millim. across from apex to apex of the 

 two lateral teeth ; they are enormously abundant in the head 

 and pinnas, forming a dense incrustation upon the latter, 

 especially upon their inner surfaces (PI. XV. fig. 2). (2) Large 

 sigmata (PI. XV. figs. 9, 10), measuring O'll by 0*0042 

 millim. ; also very abundant. 



Locality. Station 169, July 10, 1874, lat. 37° 34' S., long. 

 179° 22' E. North-east from New Zealand, 700 fathoms, 

 blue mud ; bottom temperature 40° Fahr. 



This species is very remarkable (1) for its minute size, 

 (2) for its peculiar external form, and (3) for the structure 

 of tbe small end of the chel^. 



It is, with a single exception, the smallest sponge known 

 to me ; the exception is Ghondfocladia clavata, Ridley and 

 Dendy *, which belongs to a closely-allied genus, and is only 

 slightly smaller than the present species, which it resembles 

 somewhat in external form. In considering the size, how- 

 ever, the possibility must of course be borne in mind that the 

 single specimen present may be not yet full-grown. 



As regards external form, Cladorhiza pentacrinus is a very 

 good example of the general rule that all deep-sea Monaxonida 

 have a definite and symmetrical shape t- It makes some 

 approach to the " Crinorhiza-ioxm.'''' found in other deep-sea 

 species of the genus, but it differs from all species possessing 

 that form in having the pinnse short and curved inwardly. This 

 peculiar curvature of the pinnas suggests the possibility that 

 they have the power, in life, of bending and unbending like 

 the arms of a crinoid. They differ very markedly in appear- 

 ance from the long, rigid, radiating pinnfe of typical Grino- 

 rhiza-ioYvn^ (e. g. Cladorhiza longipinna^ Eidley and 

 Dendy |), the function of which processes is doubtless to sup- 

 port the sponge on the soft mud on which it lies. This 

 function of support cannot be fulfilled by the pinnaa of Clado- 

 rhiza pentacrinus, because, in the first place, they are not 

 disposed in a suitable manner, and, in the second place, it is 

 almost certain that the body of the sponge is raised far above 



* Report on the MonaxoBida dredged by H.M.S. ' Challenger,' p. 100, 

 pi. XX. hgs. 1, la. 

 t Cf. Report on the ' Challenger ' Monaxonida, p. 262 

 X Ibid. p. 92, pi. XX. fig. 2. 



