27 



tion vertically upon the periphery of the inner sarcode body, 

 which gives off, through the outer region, and reaching beyond 

 the radiating spicida, a variable number of very slender, deli- 

 cate, non-coalescing granuliferous pseudopodia. 



It will be seen that, in the generic characters, I have claimed 

 for Acanthocystis, as in some other new genera, two differ- 

 entiated strata of the sarcode mass ; the inner one is, of course, 

 that within the cavity, the outer is not so perceptible, yet 

 I think can be readily seen with close examination as a pale, 

 colourless, granular, rather plastic, investment to the radial 

 spines. It is not, I think, conceivable how these could ori- 

 ginate, merely touched to the surface of the inner body-mass; 

 they would not grow like a plant just in contact and no 

 more, or even slightly immersed in the upper surface of the 

 inner body : they must be deposited by sarcode. This outer 

 sarcode region, I believe I readily see in living examples ; and 

 though I do not find it msisted on by Grenadier or Greef, 

 I think I see it well depicted in the figures of the latter. I 

 think that in Acanthocystis this differentiated outer sarcode 

 region exists just as truly and as marked as in Raphidiophrys, 

 Heterophrys, or Pompholyxophrys. 



It will be further seen that I have left out any allusion in 

 the foregoing characters to the assumed more or less curved 

 tangental spicula, described by Carter as characteristic, inas- 

 much as I now conceive they are not of any essentially dif- 

 ferent nature, nor, indeed, even necessarily, present. Even 

 when present, I should now, upon re-examination of the two 

 Irish forms, quite coincide with Grenacher's suggestion that 

 they represent but the discoid bases of certain of the spines, 

 whose shafts have not become developed. If they were 

 truly linear or arcuate, or crescentiform spicula, as Carter 

 represented, and as I had myself long thought, though 

 always puzzled about it, they should naturally be ajjparent 

 on the upper jDortion of an example when focussed by an ob- 

 server, and yet I could not perceive them ; they, in fact, only 

 appear linear when seen edgeivays at the periphery of a 

 specimen. These apparently distinct spicula, that is, the 

 bases of the spines, are, of course, really circular, and appear 

 so when viewed at the near or upper portion of a specimen, 

 but they are very pellucid, and hence hard to be made out, 

 even with accurate focussing, and this seems to me to account 

 for the puzzle that the assumed linear spicida could be seen 

 only at and towards the periphery. 



So far, then, as I can see, the foregoing diagnosis lays 

 down all that can be as yet absolutely stated as appertaining 

 to the genus of which Carter's A. turfacea is the type. 



