194 
THE VOYAGE OF H.M.S. CHALLENGER. 
Remarks. — Norman^ first pointed out the similarity of Ecionema ponder osa^ Bk., and 
Stelletta aspera, Crtr., at the same time stating that the only spicules of Bowerbank’s 
sponge absent from Carter’s are certain “ cylindro-doliolate ” forms which Bowerbank had 
the acumen to observe, but which might have easily been overlooked by Carter ; as this 
supposed form of spicule is introduced into Bowerbank’s descriptions of various other 
species of sponge,^ it may be as well to mention here that the “ cylindro-doliolates ” are 
nothing else than short cylindrical fragments of oxeate spicules ; they are not uncommon 
in mountings of sponge spicules, and almost always, if not invariably, present one or 
two transverse cracks in the middle, which, as well as the general characters of the broken 
bits, are faithfully represented in Bowerbank’s drawings. 
St7'yphnus rudis, n. sp. 
Sponge. — Large, massive, depressed, irregularly lobate ; oscules in irregular sieves at 
the ends of the lobes, and on the under surface ; surface densely and coarsely hispid. 
Spicules. — I. Megascleres. 1. Ectosomal oxea, fusiform, attenuately pointed, 7‘0 by 
0'0725 mm. ; Choanosomal oxea, similar, 2'86 by 0'064 to 3'03 by 0'055 mm. 
2. Plagiotrisene, rhabdome straight, conical ; cladi conical, curving outwards and 
forwards, giving a cup-like outline to the cladome ; dimensions variable. Rhabdome 1'24 
by 0‘67 mm., cladi 0'716 mm., chord 0'954 mm.; and rhabdome 1‘03 by 0‘084 mm., 
cladi 0'876 mm., and chord 1‘27 mm. 
3. Dichotrisene, rhabdome 1 033 by 0045 mm., protocladi 0’16 mm., deuterocladi 
0'366 mm. long. Transitional forms occur between this form and the plagiotrisene ; in 
an example with two bifurcate cladi and one simple cladus, the dimensions are — rhabdome 
1'45 by 0‘064 mm., simple cladus 0’621 mm,, protocladi 0'223 mm., and deuterocladi 
0’366 mm. long. The esactine of the trisenes is frequently cladose near its extremity, 
and sometimes dichocladi proceed from it at right angles. . 
II. Microscleres, 4. Ectosomal amphiaster, from 0'012 to O'OIG mm. in length; 
actines about 0'005 mm. long. 
5. Choanosomal oxy aster, centrum absent, actines not numerous, slender, conical, 
from 0‘024 to 0 0 3 2 mm. in length. 
Colour. — Blackish-brown. 
Habitat. — Kors Fjord, Norway (Rev. A. M. Norman). 
Remarks. — The single specimen of this sponge measures 200 mm. in length, 160 mm. 
in breadth, and 85 mm. in height. The excurrent canals cross the cake-like mass from 
the upper to the lower surface, and run longitudinally through the lobes ; they are of 
1 Bowerbank, Mon. Brit. Spong., vol. iv. p. 30. 
2 E.g., in Geodia media, Bwk., Proc. Zool. Soc. Lond., 1873, pi. ii. fig. 29. 
