6 PRor. E. A. MiNCHiN ON THE [May 2, 



The specimens of this sponge which I have studied nearly all 

 came from Banyvils-sur-Mer, where this species is extremely abun- 

 dant. By the kindness of Monsieur Topsent, however, I have 

 seen a specimen from Roscoff, not differing in any respect from the 

 Mediterranean specimens. The sponge therefore has a wide range 

 of distribution, and is almost certainly to be ranked as a member 

 of the British Fauna, though it does not appear to be common on 

 our coasts. Hanitsch has, indeed, recorded it fi'om Liverpool : 

 I have no reason to doubt the correctness of this record 

 beyond the fact that my experience of specimens labelled coniorta 

 by the most eminent authorities has left me very sceptical as to 

 the correctness of any identification of this species which I have 

 not checked ; a scepticism heightened, in the present instance, by 

 the fact that Hanitsch names his specimens Asccdtis contorta. I 

 may add that the sponges named Ascandra contorta by Breitfuss 

 in various memoirs have nothing to do with this species, and 

 should not therefore be taken into account in considering its 

 geographical range. 



At Banyuls-sur-Mer Clathrina contorta is not only one of the 

 commonest, but also one of the largest Ascons occurring there. 

 Colonies frequently measure 8 centimetres or more across. They 

 consist of a massive or spreading growth of twisted anastomosing 

 tubes, running in all planes, and forming a dense feltwork from 

 which arise at intervals the short, straight, not veiy conspicuous 

 oscular tubes, which reach two or three millimetres in height, 

 and are of slightly larger calibre than the body-tubes, as the basal 

 growth may be called. The body-tubes are centred round the 

 oscular tubes more or less distinctly, and in the region of the 

 oscular tube the basal system of tubes is usually slightly raised up 

 to form a conulus bearing the oscular tube on its summit ; but 

 these convili are generally very shallow, so that the upper surface 

 of the spreading colony is nearly flat, not lobiilated like that of 

 cerebrum, nor cushion-like, fis in reticidum — two species occurring 

 commonly with contorta, but both very easily distinguished from it 

 at sight. Photographs will make the external characters of contorta 

 clearer than any description (Plate I.). Of its allies, it is perhaps 

 coriacea with which contorta might be most easily confused, on 

 simple inspection ; the latter, however, with its greatly developed 

 gastral rays, is not found contracted up, with closed oscula, like 

 coriacea, and when expanded its body- wall is much thicker and 

 less delicate. 



The spiculation of Clathrina contorta comprises in typical 

 specimens all the three kinds of spicules found in calcareous 

 sponges. 



The triradiate systems are equiangular, with the rays straight, 

 tapering imperceptibly for the proximal half or two-thirds ; after 

 that tapering more rapidly to a sharp or moderately blunt point 

 (text-fig. 2, 1 a-\f). The distal extremities of the rays are often 

 irregular in outline, sometimes markedly so. The rays vary in 

 length from 80 to 130 /x in difierent specimens, but may be said 

 to average 90-100 /i. The breadth at the proximal end of the 



