218 MISS I. B. J. soLLAs ON THE [June 17, 



Tetraxonia. 

 Carxosa. 



22. Dercitits plicatus Toijsent. 



Dercitus jdicatus Topsent, Arch, de Zool. Exp. (3) iii. p. 493 

 (1895). 



Sponge gi'owing- on a vah-e of lamellibranch shell. Pinkish. 

 Surface uneven. 



Spicules calthrops - like microtriagnes and spined microxeas ; 

 microdichotiisenes absent. 



The spicules have a somewhat wider range of size than those 

 of Topsent's specimens. 



Orthotria;nes, cladus 0-10~0-24x 0-01 5-0-027 mm. 



Microxeas 0-01 2-0-025 x 0-002-0-003 mm., including the spines. 



Great Redang. 



23. Dercitus pauper, n. sp. (Plate XY. fig. 1.) 



Sponge pink, encrusting. The specimen is growing on a piece 

 of dead coral skeleton ; it forms a long narrow band about 

 50 X 5 mm. and 1 or 2 mm. thick. Surface smooth and shining. 

 No oscula visible. 



The megasclei-es ai-e small dichotrisenes or simple calthrops-like 

 microti-isenes (the latter spicule i-are). The megascleres ai-e 

 sparsely distributed, conti-asting with the intei-locking spicules in 

 JJ. plicatus. 



Dichotrifene, protocladus 0*05-0-06 x 0-01 ; deuterocladus 0-03 ; 

 rhabdome 0*08 mm. 



Orthotrifene, cladus 0-06-0*07 X 0-003 mm. 



Spined microxeas 0-015-0-02x0-001 mm. 



Great Redang. 



24. Samus anoxyma Gray. 



Samtts anonyma Gray, P.Z.S. 1867, p, 526; Caiter, A. M. N. H. 

 ser. 5, vol. iii. p. 350 (1879) ; SoUas, Voy. of H.M.S. ' ChaUenger,' 

 vol. XXV. p. 57. 



Sponge growing on a lainellibranch shell in company with 

 Terpios fttgax and Uymedesmia hallezi. 



The measurements of the spicules agree with those given in 

 the ' Challenger ' Monograph. 



Pulau Bidang. 



Tetractinellida. 



25. Tetilla ridleyi SoUas. 



Tetilla ridleyi Sollas, ' Challenger ' Monograph, xxv. p. 48. 



Sponge hemispherical ; surface i-ough ; oscula few, small, with 

 slightly raised rims, forming an interrupted ring round the sponge. 

 l^iameter of base about 16 mm. 



Oxeas 2-16x0-026 mm. 



Protrifenes, cladus 0-037-0-14 mm. 



