SPONGES FEOM THE MEKGUI AECHIPELAGO. 



67 



ierize the species. Size of specimen about 4 inches high and 

 5 inches broad. 



Dict rocTLiNDKUS aceeattts, n. sp. (Plate Y. figs. 3-6.) 



A small, ragged, branched specimen, of globular form and grey 

 colour, about 2 inches high and 2h inches in horizontal diameter. 

 In its rough aculeated appearance it strongly resembles D. rugosus, 

 Bowerb., but is widely different in spiculation from it and the 

 British species generally, inasmuch as the fibre is chiefly composed 

 of acerate spicules, from which the acuates spring in long setaceous 

 tufts on the surface, accompanied at the base by short, clavate, 

 sharp-pointed, capitate, and spined echinating spicules. The 

 acerate spicules are smooth, cylindrical in the middle, and pointed 

 at each end, rather bent than arched in the centre, varying in 

 size from less than 50-1800ths by l-1800th inch downwards ; 

 while the acuates, as usual, consist of stout and comparatively 

 short spicules, mixed with thin and long setaceous ones. 



Loc. King Island. 



Obs. The most characteristic point in this species is the pre- 

 sence of the acerate spicule ; hence it has been designated 

 " aceratus " after this peculiarity. 



Miceociona acebato-obtusa, n. sp. (Plate Y. figs. 7-10.) 



Adnate, spreading, almost immeasurably thin. Colour brown. 

 Spicules consisting of long, setaceous, thin, mixed with shorter, 

 stout acuates, for the most part obtusely pointed and micro- 

 spined over the large end, but not inflated there ; and of tri- 

 curvate flesh- spicules and minute, navicular equianchorates lying 

 at the base of the acuates. Size variable. 



Loc. King Island. 



Obs. The obtuse end3 of the acuates of this species led to the 

 specific name ; this point, together with the absence of a spinous 

 echinating spicule, causes it to differ from the species hitherto 

 described. In one specimen, viz. No. 20, the sponge presents 

 itself under the form of short, obtuse, mammillary processes about 

 I inch long and ^ inch in thickness ; but as it here covers the 

 tubes of Serpulce, I am not certain that these prolongations are 

 not the oral ends of the latter, over which the Microciona had 

 grown, and which it had subsequently replaced by its own tissue, 

 as I have never before seen prolongations from the surface of 

 any species of Microciona that has come under my observation. 



