284 HYALONEMA (PRIONEMA) PINTTLIFUSUM. 



in their distal and proximal portions. A more or less conspicuous conical spine 

 with a maximum height of 0.5 m arises from the centre of the apex of the 

 anchor. The anchors are very frequently irregular in so far as some teeth are 

 considerably longer than the opposite teeth (Plate 106, figs. 21-23, 25). 



The nearest ally to H. (P.) crassum is H. (P.) spinosum (p. 273). From this 

 H. (P.) crassum differs chiefly: — by possessing macramphidiscs with short and 

 broad anchors and smooth teeth ; by the anchors of the serrated macramphidiscs 

 being somewhat differently shaped ; by the absence of the spicules there described 

 as small macramphidiscs; by the largest micramphidiscs attaining a much larger 

 size; by the presence of stout paratangential rhabds (tignules) in the superficial 

 membranes; and by having longer pinules. 



Hyalonema (Prionema) pinulifusum, sp. nov. 

 Plate 70, figs. 11-24; Plate 71, figs. 1-11; Plate 72, figs. 1-15. 



I establish this species for a fragment trawled off the south coast of western 

 Panama at Station 4621 on 21 October, 1904; 6° 36' N., 81° 44' W. ; depth 1067 

 m. (581 f.) ; it grew on a bottom of green mud and rock; the bottom-temperature 

 was 40.5°. It possesses large pinules with distal rays greatly thickened in the 

 middle and markedly fusiform in shape. To these the name refers. 



Shape and size. The specimen is a flat fragment, 14 cm. long, 8 cm. broad, 

 and with a maximum thickness of 1 cm. The margin is lacerated. The speci- 

 men is composed of lamellae about 1 mm. thick, separated bj^ wide cavities. 

 It probably formed part of a lamellar or cup-shaped sponge. 



The colour in spirit is brown. 



The skeleton. On many parts of the surface the pinule-fur is still more or 

 less intact. A number of small wart-like protuberances, 0.5-1.5 mm. broad 

 and high, arise on one side of the lamellar body. These bear on their summits 

 dense masses of medium-sized pinules. Much larger scattered pinules with 

 stout, spindle-shaped distal ray arise from the walls of the wide depressions be- 

 tween these protuberances. Pinules of the same kind densely cover the margins 

 of some of the lamellae oil the other side of the sponge. Other parts of the thin 

 lamellae bear sparse, small pinules, with relatively few and small spines on the 

 slender distal ray. Besides these three kinds of pinules, a fourth kind, with distal 

 rays terminating in a rather long and slender terminal cone and with large second- 

 ary spinelets on the primary spines of the distal ray, has been found quite 

 frequently in the preparations. These pinules are identical with certain pinules 



