310 ERYLUS CAI.ICULATUS. 



Cortical armour composed chiefly of asj)i(lasters. Rliabcl megascleres 

 chiefly sharp-pointed amjihioxes; 440-050 Iiy S 12 /(. Rhalxl-ckisters 125- 

 180 ,H Ions;;. Microrliabds gradually and sharply ])ointed, more or less centro- 

 tyle; 32-50 by 2-4.5 /«. Triaenes; rhabdome lSO-190 /« long; cladome 300- 

 440 n broad. Acanthtylasters with two or more rays; 12-31 /t in diameter. 

 Oxy;i.sters 8-14 /( in diameter. Aspidasters 65 75 by 62-69 by 5-7 /<; average 

 ])roportion of length to breadth to thickness ]0():U(i:0.2. 



South coast of Mohjkai. 



The structure of the canal-system and s])iculation of tliese sponges clearly 

 show that they belong to Erylus. They differ consideral^ly from all the species 

 of this genus previously descrilied, l)y the nearly circular shajie and the small 

 ^ size of their a.s]iidasters and other characters. Their nearest ally is the species 

 here described as Erylufi caliculutus. By its shape being caliculate, by its micro- 

 rliabds being amjihistrongyle insteatl of amphiox, by its aspidasters being larger, 

 relatively much thicker, and jiartly reniform in sluqje, and by its s])icules gener- 

 ally being larger and much stouter, this si:)onge differs from E. rolundus to 

 such an extent, that it must be considered sjiecifically cUstinct from it. 



Erylus calicu'.atus, sp. nov. 



Plate 5, fi.i.'s. G-IO, 24, 25 29; Plate 6, figs. 1 -K!, 19-2:5, 2(). 2S, 29; Plate 7, fi!,'.s. 11-15, 31-41, 71, 77, 

 7S, SO; Plale S, ligs. 1-12, l.-)-2(). 



I establish this species for a sjiecimen obtained on the northeast coast of 

 Hawaii (Station 4062). The name refers to its caliculate shape. 



Shape and size. The sponge (riate 6, fig. 29) aj^pears as a broad, low, 

 truncate, inverted cone. It is 33 mm. high. The base of the cone, which forms 

 the upper side of the s])onge, is iiT(>gularly oval in outline, depressed in the 

 middle, 47 iron, long, and 36 mm. broad. Its elevated margin is rounded, about 

 6 nmi. thick, and jxartly divided into lobes. The base of attachment, which 

 corres])onds to the truncate summit of the cone, metisures 30 by 18 mm. The 

 surface is uneven and covered with shallow grooves, 0.5-1 mm. broad. These 

 grooves are particularly well market! on the protruding marginal lobes. Nu- 

 merous small circular i)ores, up to 0.3 mm. in diaineter, are scattered over the 

 sides of the sponge. Apertures occur also on its depressed upper face, but 

 these are not so numerous and less uniform in size than those on the sides. 

 The largest of these ajMcal a])ertures, which I am inclinetl to consider as oscules, 

 measure 1 mm. in diameter. The margin is free from i)ores. 



