480 " THETIS " SCIENTIFIC RESULTS. 



Texture resilient, fairly tough. Colour yellowish-grey. In 

 washed out specimens the fibres have a silk-like appearance. 



The dermal surface is unfortunately denuded in all the 

 examples available ; subdermally it is highly porous throughout 

 and exhibits numerous oscula having a series of circular aper- 

 tures — about 1 mm. in diameter— arranged in clusters of three or 

 more, with radiating grooves in which are situated a number of 

 pores of various sizes. 



Skeleton consisting of a series of well developed horny fibres ; 

 the primaries are arranged longitudinally and are provided with 

 four or more spicules in a row ; as they approach the surface 

 they increase in diameter and converge to form the clusters of 

 conuli ; here the axial spicules become very numerous and occupy 

 the whole of the fibre. The secondaries are mostly unispicular, 

 whilst the connecting fibres are generally free from spicules. 

 The main fibres measure about 0*15 mm. in diameter, the 

 secondaries 0-5 mm., and the connecting 0-015 to 0-02 mm. 

 The mesh is subquadrangular or oblong and generally about 

 0*25 mm. wide. The main reticulation is often obscured by 

 numerous slender fibres which are extremely irregular in their 

 arrangement. 



Megascleres : — straight or slightly curved oxea, gradually 

 tapering from the middle to acute points. Size 0"17 by 0-01 mm. 



Microscleres : — sigmata very variable in shape and size ; some 

 are simple, others contort ; many examples are C- or U-shaped, 

 with acute ends, which are sharply bent inwards. Size from 

 0-025 mm. to 0-1 mm. Owing to the washed out condition I 

 have failed to find any chelae that I could safely say belonged 

 to this form. 



This species is allied to Desmacidon car^iosa, Carter. It is, 

 however, quite distinct, as I have compared the species here 

 described with Carter's type. 



Subfamily DENDORICIN^, Topsent 

 DENDOKYX, Gray. 



DENDORYX PUMICEA, sp. nov. 



(Plate xliv., fig. 15.) 



Station 47. 



Sponge flabellate, growing on the stem of a Gorgonia. The 

 general contour is evidently in keeping with its support ; the 

 height is 225 mm., the breadth 140 mm., and the thickness from 



