PORIFERA. II. 39 



118, PI. Ill, figs, i, i a— d; ibid. Ser. 2, II, 1896, Sect. 4, 188, figs. 7, 7a— d) 1 ); Lambe mentions two 

 kinds of styli, rather thick ones with short point, and thinner ones with long evenly tapering point, 

 but the latter I take to be developmental forms, these having always a longer point than the fully 

 developed ones. 



4. M. thaumatochela n. sp. 



PI. X, Fig. 2 a— g. 

 1897. Esperella intermedia Vanhoffen (non Schmidt), Gronland Exp. der Gesellsch. fiir Erdkunde zu 

 Berlin, II, 1, 248. 



Incrusting, The surface shaggy from projecting bundles of spicules ; the dermal membrane thin. The 

 skeleton a tolerably regular network of polyspicular fibres. Spicula: Megasclera styli 0-35— o- 48'"'"; microsclera 

 of two forms, anisochelce palmata- 0-047—0-06'""', anisochelce of a very peculiar structure 0-012— o-o //""". 



Of this sponge we have only one small specimen growing on a fragment of a shell of Pccten 

 islandicus, and a small, inconsiderable, loose fragment. As to the exterior the sponge is very insigni- 

 ficant, and all the interest attaches to the spicnlation. The specimen is formed as a very thin incru- 

 station, and its greatest extent is i5 mm ; but it looks, however, as if the whole specimen is not found on 

 the fragment of the shell. The thickness is at most i mm . The colour (in spirit) is light grayish-brown 

 The surface is shaggy from projecting bundles of spicules. There is a thin dermal membrane, without 

 spicules as far as I am able to see. In the dermal membrane circular openings are found, of a dia- 

 meter of 0-047 — °'35 mm °f which I take the greater ones to be oscula, and the smaller ones pores. 



The skeleton consists of polyspicular fibres; as far as I have been able to examine the material, 

 it is formed of fibres running from the base to the surface and projecting through the dermal mem- 

 brane, and of other fibres perpendicular upon the former ones; it seems to be rather regular. In the 

 nodes a slight amount of spongin is seen. 



Spicula: a. Megasclera are styli, evenly and most frequently slightly, sometimes a little 

 irregularly curved. They have an even point of middle length, which is often somewhat shorter pointed 

 at the outer end. The size of the styli is rather constant, the length is between 0-35 and o^S 01 ™, and 

 the thickness is 0007—0-0115""". b. Microsclera. These are of two kinds, anisochelse palmatae, and 

 some small, peculiarly shaped bodies which may also be characterized as anisochelse. 1. The palmate 

 anisochelse are of a fine regular form and chiefly of the common type. The alse of the larger end, 

 which are much refolded on the side, diverge downward with their lateral edges, and then they curve 

 somewhat upward with a round bend going in to the shaft; the tooth is somewhat narrower than the 

 alse, elliptical, but broadest below and rounded, sometimes with a small pointing. The tooth and 

 alse of the lower end are of about equal breadth ; in the middle of the distal edge of the tooth is generally 

 found a pointing owing to the axis continuing quite to the end, and on either side of the pointing is 

 found a little notch, so that the tooth is tridentate. In each end there is a longish tuberculum. The 

 size of these chelse is rather constant; the length varies from 0-047— o-o6 mm being most frequently about 



') Lambe, in both places, writes sp. nov., and has no reference in the latter place; but as the descriptions are 

 almost equal, I suppose it to be his opinion that the species is the same. Otherwise Schmidt has already in 1862 (Spong. 

 adriat Meer) established an E. modesta, so that the name of Lambe's species, at all events, must be changed. 



