SPONGES. 197 



This genus, which was never diagnosed by its author, is an extremely difficult one 

 to deal with. In our Report on the " Challenger " Monaxonida, Mr. Ridley and I 

 decided to suppress it as a synonym of Hymeniacidon, but it has lately been revived 

 by Thiele (39) as a distinct genus, and I am prepared to follow him in this respect. 

 I cannot quite see, however, why Thiele should, in the same work, have established 

 another genus (Arnorphilla) for the reception of closely similar forms (especially as he 

 gives no definite generic diagnoses), unless it be on account of the comparatively small 

 size of the spicules. 



If we decide to separate Leucophlccus from Hymeniacidon, as I think we must, it 

 must be mainly on the ground of the presence in the former of a strongly developed 

 dermal skeleton (composed, mostly at any rate, of tangentially placed spicules) which 

 often forms a white crust in dry specimens. 



Our knowledge of these sponges, however, is still very deficient, and their systematic 

 position very doubtful. I retain the genus amongst the Axinellidse on account of the 

 presence of stylote megascleres and the apparent relationship to Ciocalypta as pointed 

 out by Mr. Carter. Leucopthhcm foetidus, with its long oxeote megascleres, perhaps 

 comes nearer to Halichondria than any other species, and may indicate a close 

 relationship with the Renierinpe. 



Leucophloeus foetidus (Dendy). 



1889, Hymeniacidon (?) foetida, Dendy (3); 1897, Amorphinopsis fcetida, TorsEXT (83); 

 1898, Ciocalypta foetida, Lindgren (86). 



There is one good specimen of this sponge in the collection, differing from the type 

 as originally described in its partially trabecular and clathrous external form, and in 

 the pale yellowish (not blackish) grey colour of the surface (in spirit). 



I have already pointed out the resemblance which this species bears to Ridley and 

 Dendy's Hymeniacidon (?) subacerata, and it is not impossible that the presence of 

 the small projecting styli in the dermal membrane of both these species may ultimately 

 prove to be of generic import. 



R.N. 63 (Gulf of Manaar). 



Ciocalypta, Bowerbank. 



Axinellidfe provided with elongated, digitiform processes springing from a massive 



body. In the processes the skeleton is arranged in a plumose manner with a 



dense central axis. There is a thin dermal membrane supported on spicular 



columns and usually strengthened by a reticulation of tangentially placed spicules, 



overlying extensive sub-dermal cavities. There are no microscleres. 



Ciocalypta tyleri, Bowerbank. 



There is in the collection one specimen which I must refer to the typical form of 



this species (22). This specimen (R.N. 29), which I examined hastily in Liverpool, 



has unfortunately not been sent out to me, as it appeared to be identical with another 



which was sent instead (R.N. 29a), and the only preparation which I have of it (made 



