

Knowledge of the Spongida. 367 



arms about l-56th inch long, occasionally and abnormally 

 bifid at the extremity (fig. 7,bb); 3 and 4, anchors and forks 

 setaceous from the great length of their whip-like delicate 

 shafts, heads as usual (fig. 7, c, d) ; 5 and 6, flesh-spicules, 

 viz. the usual biharnate, 2£-6000ths inch long (fig. 7,/ and A), 

 and a thin acerate about l-100th inch long (fig. 7, g). Nos. 1, 

 3, and 4 project in great abundance beyond the surface, where, 

 from their extreme length, they not only give the hispid cha- 

 racter, but, from their inclined position, very nearly conceal 

 the vents. No. 2, in its usual position, with the shaft or one 

 ray inwards, is confined to the circumference, where, in 

 plurality, it forms a zonular line. Nos. 5 and 6 are chiefly 

 confined to the dermal sarcode. Pigmental cells, which are 

 abundantly scattered through the sarcode generally, about 

 l^-6000ths inch in diameter, charged with dark brown sphe- 

 rical granules, which, in combination, give the black-brown 

 colour to the sponge generally (fig. 6, i and h). Size of 

 specimen about 10-1 2ths inch in its greatest horizontal dia- 

 meter, which is between the base and the summit, 6-12ths 

 inch high. 



Hob. Marine, growing on hard objects. 

 Loc. King's Island, Mergui archipelago, coast of Burmah. 

 Obs. The black colour, together with the presence of a cir- 

 cumferential line of zone-spicules, distinguishes this species 

 from Tethya cranium. As far back as 1869 I noticed the 

 presence partially of zone-spicules in Tethea arabica y and 

 afterwards in an un described species generally, as before 

 noticed ; but they differed from those above described in the 

 possession of a long shaft and shorter arms, thus more resem- 

 bling the zone-spicule of Geodia &c. (PI. XV. fig. 9). The 

 reticulated fibro-dermal structure covered by a layer of sarcode, 

 rendered dark and cribriform by the pores, the pigmental cells, 

 and the flesh-spicules, recalls to mind a similar structure in 

 Thenea Wallichii, just below the margin of the pileus, being 

 equally striking and beautiful (fig. 8, ccc). 



I have only met with one specimen of Tethya merguiensis ; 

 and that is among the collection of sponges made by Dr. 

 Anderson, to which I have alluded. It is accompanied by two 

 sessile specimens, so nearly allied to Tethya cranium that I 

 have designated them as " var. robusta " in my MS. report, 

 which it is the intention of Dr. Anderson to publish with those 

 of the other Invertebrata collected by him at the same time. 

 Besides these there are the several specimens of Tethya dacty- 

 loideaj to which I have above alluded ; so that the Tethyina 

 are richly represented in this locality. 



