112 BRITISH 8PONGIAD. 



35. HALICHONDRIA NIGRIOANS, Sow., 11, 2G6; in, PI. 



XLV, figs. 2531. 



1867 loplion nigricans, Gray. Proc. Zool. Soc., p. 534. 



36. HALICHONDEIA ALBULA, Bow., n, 268; in, PI. XLY, 



figs. 2124. 



1867 Dendoryx albula, Gray. Proc. Zool. Soc., p. 536. 



37. HALICHONDEIA EXPANSA, Bow., in, 212, PI. LXXIV, 

 figs. 712. 



1869 Halichondria expansa, Bowerbank. Norman, Notes on 

 a few Hebridean Sponges, Ann. Nat. Hist., ser. 4, 

 vol. iii, p. 298. 



38. HALICHONDEIA VIEGEA, Bow., n. sp., iv, PI. Y, 

 figs. 17. 



1875 Halichondria virgea, Bowerbank. Report Dredging off 

 the Durham and N. Yoikshii'e Coasts, Brit. Assoc. 

 Rep., 1875 (1876), p. 198. 



" Sponge massive, sessile, more or less nodulous. 

 Surface smooth. Oscula simple, dispersed. Pores in- 

 conspicuous. Dermal membrane abundantly spiculous, 

 tension spicula acuate, very long and slender, nume- 

 rous, fasciculated ; retentive spicula bidentate, equi- 

 anchorate, large, few in number, and the same form, 

 small and numerous. Skeleton rete more or less 

 regular, fibres rarely multispiculous, seldom more than 

 trispiculous ; areas large ; spicula subfusiforrni acuate, 

 basally spinous. Interstitial membranes spiculous ; 

 spicula same as those of the dermis ; tension spicula 

 of rare occurrence ; retentive spicula rather numerous. 



