sponges from the Atlantic Ocedn. 309 



Cornulum textile^ n. sp. (PI. Xll. fig. 9, and PI. XV. 



%. 28, a, h.) 



General form an obconic sheath, horn-shaped, more or less 

 twisted or bent upon itself, fixed bj the narrow end, open at 

 the large one, which is filled up by a protruding portion of 

 the internal structure. Colour yellowish white. Surface of 

 the sheath or dermis smooth, presenting a number of circular 

 ridges marking the degrees of growth ; composed of a horny 

 sarcodic membrane densely charged with spicules, so as to 

 resemble a textile fabric (PI. XII. fig. 9, a). Pores and vents 

 probably in the protruding mutilated head, in which, as usual 

 in the histodermal forms, the structure is so delicate that all 

 the soft parts are broken down into a confused pulp. Internal 

 structure (fig. 9, h) consisting of a conical fibrous mass corre- 

 sponding in form with that of the sheath, consisting of bun- 

 dles of spicules dividing and subdividing from the conical to 

 the expanded end, where they terminate in thin plumose 

 lacinulations ; supporting throughout the internal sarcode and 

 excretory system, before the sarcode becomes broken down. 

 Colour yellowish white. Spicules of two kinds, viz. skeleton- 

 and flesh-spicules. Skeleton-spicules of two forms, viz. : — 1, 

 large, subfusiform, smooth, sometimes slightly inflated at the 

 ends, which are round and microspined, 27- by 1-1 800th inch 

 (PI. XV. fig. 28, a) ; 2, subskeleton-spicule, extremely thin, 

 acuate, smooth and pointed, subundulous, 32-55-6000ths by 1- 

 18,000th inch (fig. 28, b) . Flesh-spicules of two forms, viz. : — 

 1, very small, equianchorate, navicular, 3-6000ths inch long 

 (PI. XII. fig. 9, e) ] 2, tricurvate or bow-shaped, smooth and 

 pointed, 30-6000ths inch long (fig. 9, d). The large skeleton- 

 spicules, which are the only ones that appear under an inch 

 object-glass, are chiefly confined to the sheath and the fibrous 

 bundles forming the skeleton of the internal structure, while 

 the rest are distributed generally throughout the broken-down 

 sarcode. Size of specimens about one inch long by a quarter 

 to half an inch in diameter at the widest end. 



Hab. Marine, attached to hard objects. 



Loc. About 40 miles N.W. of the Shetland Islands, in 

 345 fathoms. 



Ohs. These specimens, of which there are three, are con- 

 tained in jars bearing the same number, viz. " Qb,^'' which 

 gives the locality and depth above mentioned. One is accom- 

 panied by a fragment of Halichondria panicea. The spicules 

 generally and their arrangement in the skeleton point to the 

 second division of the Echinonemata, viz. the Axinellida, espe- 

 cially as many of the large ones have a tendency to an acuate 



A7in. & Mag. N. Hist. Ser. 4. Vol. xviii. 21 



