160 Mr. H. J. Carter on Parasites of the Spongida. 



as represented in the ' Annals ' (the former in 1869, vol. iv. 

 pi. vii., and the latter in 1871, vol. viii. pi. ii.). 



3. Polyps single J double^ concatenated or irregularly grouped ; 

 sunk into a scleroderma upon^ hut not into, the surface of the 

 sponge; circumference of the polyp defined hut not marginated, 

 about l-12fA inch in diameter. 



See especially Echinonema typicum, Cart. MS. (Echinone- 

 mata, fam. Ectyonida, group 1. Pluriformia, op. cit. p. 143, 

 &c.). From Freemantle, S.W. Australia. Very common on 

 the branched digitate form. 



4. Polyps single, double, or irregularly grouped, more or 

 less pendent from their scleroderma, situated upon the surf ace of 

 the sponge ; sometimes l-4:th inch long. 



Ex. gr. Axitiella damicornis, Sdt., and A. verrucosa, Sdt. 

 (Spong. Adriat. Meeres, Taf. vi. figs. 2 and 3 respectively, 

 1862). Palythoa axinelloi is Schmidt's name for this polyp, 

 which is more pendent but smaller in the head than the fol- 

 lowing species, viz. Palythoa fatua, M. Schultze (' Hyalo- 

 nemen,' 1860, S. 21, ff), which grows over the upper part of 

 the glass cord of both Hyalonema Sieboldii, Gray, from Japan, 

 and H. lusitanicum, Boc, from the Atlantic, on the coast of 

 Spain and the north of Scotland. See H. mirabilis, Gray 

 (Proc. Zool. Soc. Lond. 1857, =//. Sieboldii, Gray, 1835, 

 ib.), partly copied into Dr. Bowerbank's ' Mon. Brit. Spong.' 

 vol. i. p. 287, pi. XXXV. f. 374, where the polyps are consi- 

 dered by Dr. Bowerbank to be the " oscula " and not the 

 " inhalant areas " of the sponge, as stated and delineated in 

 fig. 308, t*6., before mentioned! This somewhat ficoid species 

 occurs on the depressed and sessile forms of TetJiea muricata, 

 var., Bk., =iV(3rmawta crassa, Bk. (Mon. Brit. Spong. vol. iii. 

 1870, pi. Ixxxi. fig. 1), where there is a group of four figured 

 without indication, on the right side of the median line close 

 to the upper margin, which I recognize here, especially, 

 because the same thing occurs on a similar specimen dredged 

 up on board H.M.S. ' Porcupine ' between the north of Scot- 

 land and the Faroe Islands. 



With reference, however, to Duchassaing de Fontbressin's 

 statement before quoted, viz. that the parasitic polyps of 

 sponges to which he alludes do not occur on any other marine 

 organisms, there is, in the British Museum, a flat, elliptical, 

 sessile mass or colony of Hydroid podocorynid polyps about 

 three inches long and one tenth of an inch thick, whose deli- 

 cate, erect, colourless filaments in juxtaposition, like the hairs 

 of a clothes-brush, rising from a tough matted mycelium, 

 present an even surface of hydranths on the top sufficiently 



