PORIFERA. III. 



54 



oxeata; the greatest extent to which it reaches is i6 ram . The colour (in spirit) is whitish to light 

 yellowish. The surface seems, in the places where the sponge is undamaged, to be without projecting 

 spicules. The dermal membrane is a thin film with close-lying chelae. 



The skeleton. The dermal skeleton ; the dermal spicules form fibres or bundles, which under 

 various arrangements stretch more or less obliquely from the interior of the sponge out to the dermis; 

 thev may also be found in or below the membrane as horizontal bundles; the fibres may be of a 

 considerable thickness; besides, the membrane has close-lying chelae. The main skeleton consists in 

 the ordinary way of more or less vertical acanthostyli with their heads attached to the substratum; 

 the styli are placed somewhat dispersedly. Spongin was not observed. 



Spicula: a. Megaselera. i. The skeletal spicules are acanthostyli with a more or less 

 marked, but small head and they taper into a long, fine apex; they are curved, and the curvature 

 lies nearest to the head, it is found both in the large and small styli, for which latter it is 

 especially characteristic. The spinulation is not strong; in the longer styli there are larger spines 

 only on the head-end, the lower part of the shaft is grittily spinulous and the larger outer part, 

 sometimes the whole shaft, is smooth; the smaller styli are a little more strongly spined and in the 

 whole or nearly the whole length. The length is in all 0-149— 065 mm ; the styli are rather distinctly 

 divided into two groups, the large not going below 0-41 mm and the small not beyond o'238 n,m ; the 

 diameter of the head is 0-014— 0-025""". 2 - Tlie dermal spicules are straight strongyla, they are only 

 very slightly thicker in the middle than towards the ends, one end is a little thicker than the other. 

 The length is 0-298— 0-35'"'" and the diameter is between 0-004 and 0-005""". b - Microsclera ; these 

 are chelae arcuatae; they have an evenly but strongly, up to nearly semicircularly curved shaft, the 

 end-parts are relatively small, the alas lobe-shaped; the shaft is somewhat flattened. The length is 

 0-035— 0-044 mn \ and the diameter of the shaft 0-004 — o-on mm according as it is seen in profile or 

 in front view. The chelae occur numerously in the dermal membrane and sparingly otherwise in 

 the tissue. 



This species stands near to H. longistylus 11. sp. (to be described hereafter), but it is distingushed 

 by the more strongly curved small styli and by other dermal spicules and chelae; it is also related to 

 H. curvicbela, but also from this it is distinguished by the characteristic, curved small styli. The 

 species must moreover be allied to H. (Hymeniacidon) paupcrtas Bow. but the small styli figured for 

 this species, and also the figure of the chela; seem to prevent identification. 



Locality: Station 1, 62 30' Lat. N., 8° 21' Long. W., depth 132 fathoms; station 9, 64 18' Lat. N., 

 27 00' Long. W., depth 295 fathoms; station 10, 64 24' Lat. N. , 28 50' Long. W., depth 788 fathoms; 

 station 54, 63 08' Lat. N., 15 40' Long. W., depth 691 fathoms; station 85, 63° 21' Lat. N., 25 21' Long. W., 

 depth 170 fathoms; station 89, 64 45' Lat. N., 2 f 20' Long. W., depth 310 fathoms; station 94, 64 56' 

 Lat. N., 36 19' Long. W., depth 204 fathoms; station 98, 65 38' Lat. N., 26 27' Long. W., depth 138 

 fathoms; further it has been taken at 63 12' Lat. N., 20 06' Long. W., depth 270 fathoms (The Fishery 

 investigation steamer "Thor"); and East of the Faroe Islands, depth 250 fathoms (Ad. Jensen, the cruise 

 of "M. Sars" 1902); in all about nine specimens. The localities lie in the Denmark Strait, South of 

 Iceland and East of the Faroe Islands. 



