SPONGES. 171 



The palmate isochelae may be abundant. Smooth, slender toxa of very various 

 length are also met with. These are best developed in R.N. 85 and 281, where 

 they attain a length of about 0'184 millim., being almost straight from end to end 

 except for a small bow in the middle. The stout styli of the main skeleton vary 

 greatly in thickness. The slender styli or tylostyli may form a fairly distinct dermal 

 skeleton, in which they are either irregularly scattered or arranged in more or less 

 definite radiating brushes. The bases of these spicules are sometimes minutely 

 spined (R.N. 169). 



One of the specimens (R.N. 97) is attached to a pearl oyster (Maryaritifera 

 vulgaris). 



R.N. 44, 97, 268 (all Gulf of Manaar) ; 85, 169, 281 (all deep water off Galle and 

 onwards up West Coast of Ceylon). 



Clathria indica, DENDY. 



This common species (DENDY, 3) is represented in the collection by four specimens. 

 R.N. 27, 106 (both from Gulf of Manaar, Stat. IX., &c.) ; 166 ; 291 (Ceylon seas). 



Clathria spiculosa (DENDY). 



1889, Rhaphidophlus spiculosus, DENDY (3). 



There is one small specimen of this sponge which makes a close approach to the 

 original types both in external form and spiculation. 

 R.N. 335 (Ceylon seas). 



Clathria spiculosa, var. ramosa, nov. 



This variety agrees closely with the types of the species in skeleton arrangement 

 and spiculation, but differs conspicuously in its elongated, slender, sub-cylindrical, 

 irregularly branching external form. It thus makes a very close approach to 

 RIDLEY'S Echinonema gracilis from the Mascarene Islands (16), but the megascleres 

 in the Mascarene species are much stouter. 



R.N. 168 ; 308 ; 310 ; 333 ; 368 (deep water outside pearl banks, Gulf of Manaar). 



Clathria spiculosa, var. tessellata, nov. Plate VIII., fig. 2. 



This variety again differs from the types of the species only in external features, 

 which are, however, very characteristic. The sponge consists of more or less erect, 

 thick, irregular lamellae, with the margin rising up here and there into short, 

 digitiform processes. The vents are minute and few, marginal or on the ends of the 

 processes. The most striking character of the variety, however, is the tessellated 

 appearance of the surface, due to the presence of a close, polygonal-meshed reticulation 

 of (presumably) pore-bearing grooves ; the meshes of the reticulation are about 

 1 millim. to 1'5 millims. in diameter. The general appearance of the sponge is well 

 shown in the figure. One specimen (R.N. 92 A) measures about 70 millims. in greatest 



Z 2 



