and Aniarctic Sponges. 39 



Jar No. 1. 

 Sponge, Semisuberites arctica, n. sp. (PL I. fig. 1, a-c.) 



General form funnel-shaped, hollow, with a long round 

 stem (fig. 1, a), diminishing in size to the point of attach- 

 ment; mouth subcircular, margin thick, round, undulating 

 (fig. 2, e). Colour light grej. Surface reticulate, even. 

 Pores external, microscopic ; vents internal, large, plenti- 

 fully and uuifirmlj- scattered over the inner surface of the 

 funnel (fig. 2, ci). Internal structure loose, light, composed 

 of acuate spicules united together by sarcode into bundles 

 wliich, crossing each other, produce the usual areolated tissue 

 of sponge. Spicules of one kind only, viz. skeleton, but of two 

 forms, viz.: — 1, acuate, slightly curved towards the large end, 

 smooth, and gradually diminishing towards the smaller one, 

 which is rather abruptly pointed ; average largest size l-48th 

 by l-3000th inch in its greatest diameters (fig. 3, a) : 2, the 

 same, but with a slight subterminal inflation (fig. 3, b). Size 

 of largest specimen (fig. 1) about 3 inches long by 1| inch 

 across the brim of the funnel. 



Hah. Marine, Arctic regions. Growing singly or in plu- 

 rality on hard objects. 



Loc. Smith Sound, Cape Napoleon, in 50 fths. 



Ohs. There is much interest attaching to this sponge in 

 many ways. First, it is almost identical in elementary struc- 

 ture with Halicliondria sanguinea^S o\n\^io\\ (Brit. Spong. 1842, 

 p. 133), originally described, with a figure of its spicule, by 

 Dr. Grant in 1826, under the name of Spongia sanguinea 

 (Edinb. Phil. Journ. pi. 121, fig. 9), which together with his 

 8p. papillaris are the two commonest sponges on this coast 

 (Budleigh-Salterton, Devon) , where they can be found at all 

 tides in great abundance a little below high- water mark. Se- 

 condly, Dr. Bowerbank, from the orange-colour and cork-like 

 tissue of Halicliondria sanguinea^ the tendency of its spicules 

 to a pin-like form, and the fact that, in one instance, he found the 

 identical form of flesh-spicule which characterizes Vioa John- 

 stonii, Sdt., and (as I hope soon to show) several other sponges 

 of this kind (Brit. Spong. vol. i. pi. iii. fig. 72, p. 239), 

 points out that both Semisuherites arctica and Halichondria 

 sanguinea belong to the family Suberitida, of which I also 

 hope soon to give a full account with all hitherto described 

 species in its different groups. Thirdly, a similar specimen of 

 the same sponge, but much larger, from Spitzbergen (fig. 2), 

 was presented to the British Museum by the Rev. A. E. Eaton 

 in 1873, which may easily be found by the register number 



