British Species of Sponges. 339 



on the same rock ; and the third on the valves of a small 

 bivalve shell. 



Mr. Carter writes : — " I found this sponge first beside a 

 patch of Microciona spinarcus on a clay boulder which liad 

 fallen from the New Red Sandstone cliff" [at Budleigh Sal- 

 terton] " into the landwash close to low-water mark, and 

 afterwards on a mass of small Pecten-Wko, shells drawn up about 

 ten miles off Budleigh Salterton bj a fishing-hook. VViien 

 fresh it presents the appearance of a thin, sooty-black, slimy 

 layer, extending irregularly in leprous-like patches, almost 

 as thin as silver paper, on the surface of clay boulders ; be- 

 coming brown-black when dry and assuming the form of a 

 Ihin cuticle with glistening surface irregularly papillated and 

 pierced by the pointed ends of spicules ; vents very small, 

 scattered over the surface here and there." 



The pores now visible are few, minute and generally scat- 

 tered ; on the specimen on tlie shell one or two areas of small 

 extent are observable in which the surface is reticulated ; 

 whether the intervals of the rete are occupied by pores or not 

 I cannot determine. 



In the dry state the ectosome is tough, comparatively thick, 

 and very dark coloured. 



The skeleton consists of branched columns of slightly curved 

 styles rising vertically from the base to the surface. At their 

 origin these columns are formed of compact bundles of spicules 

 pointing straight upwards and entirely imbedded in fibre ; 

 very shortly the points of the spicules begin to protrude at a 

 small angle, and the columns are echinated besides by smaller 

 entirely spined styles (hence the proposed specific name) ; 

 finally the columns terminate by the main spicules spreading 

 out in somewhat scanty brushes, which support and partly 

 penetrate tlie ectosome. In the branches the spicules spread 

 out in flattish somewhat fan-shaped brushes. The ectosome 

 contains large numbers of smooth tylota lying in horizontal 

 bundles parallel to the surface ; these last also occur at the 

 base of the sponge and sparingly throughout the choanosome 

 in the intervals of the columns. 



Spiculation. — Megasclera, three, viz. : — 



1. Styles curved, chiefly towards tlie larger end, spined at 

 the base and, more slightly, for about halfway up the spicule ; 

 average measurements about '26 x '009 millim. (tig. B, 1) . 



2. Smaller, entirely spined, straight styles, tapering from 

 base to point ; average measurements '097 x "009 millim. 

 (fig.B,2). 



3. Smooth straight tylota, rounded and slightly inflated 



