28 



THE SPONGES. 



base, tapering gradually to the point. Rays are faintly roughened, almost 

 smooth; slightly curved or straight, both types common. — — Two types 

 of macramphidisc quite similar to the spicules of Hyalonema %, which 



A third 



are shown in Figs. 13 and 16, Plate 2, are sparsely present. 



type of macramphidisc, quite like the spicule of Hyalonema %, which is 

 represented in Figs. 14 and 15, Plate 2, is present in great abundance. 

 The spicule measures 150-180 //, in length, and is connected by abundant 

 transitional forms with similar mesamphidiscs 40-60 ^ long. Micram- 

 phidiscs, of the usual character, 16-20 fi long, are abundant. 



The similarity to Hyalonema 2 afforded by the amphidiscs is striking. 



Mention may here be made of imperfect tufts of root spicules taken 

 at Stations 3381 and 3399. The spicules resemble those of the specimen 



of Hyalonema pateriferum from Station 3376. 



Hyalonema pateriferum, sp. nov. 



Plate 1, Figs. 1-13. 



Diagnosis. Body obconical to saucer-shaped, the upper surface approximately flat, 

 the under surface very or moderately convex. No main gastric cavity, bub instead a 

 comparatively large number of efferent canals covered in by the gastral membrane. Root 

 spicules thick, about 1 mm. in diameter. Characteristic micro-oxyhexacts with slender, 

 curved, and minutely denticulate rays 30-45 ^ long. Dermal pinules, slender forms ; 

 distal ray, 150-200 /x long, ending in a slender point. Characteristic macramphidiscs 

 100-200 /x long, with smooth shaft and umbels which have the shape of wide, shallow 

 bowls ; depth of umbel about J the total length, or shallower. 



Station 3376, 1 specimen; Station 3363, 1 specimen and 3 fragments; 

 Station 17 of the "Albatross'' 1900 cruise, 2 specimens. 



In the specimen from Station 3376 (Figs. 12 and 13, Plate 1), the body 

 is irregularly obconical, and is somewhat compressed in one of the morpho- 

 logical horizontal diameters. The root tuft emerges from one side of the 



■ 



base, and exhibits an open spiral curvature. The general asymmetry is 

 doubtless an individual feature, associated with the position assumed by 

 the animal in its habitat. If in the natural position the root tuft was verti- 

 cal, then the body of the sponge probably lay under a stone or some such 

 object, the gastral face looking out from under this protection. The 

 sponge body is 65 mm. high and has a greatest width of 90 mm. The 



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