sponges from the Athtntic Ocean. 309 



Cornulum textile, n. sn. (PI. XII. fig. 9, and PI. XV. 

 Ag. 28, a, b.) 



General form an obconic sheath, liorn-shaped, more or le.ss 

 twisted or hcut iiiion it.selt', fixed by the narrow end, 0[)en at 

 the hirge one, whicli 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 homy 

 sarcodic membrane densely charged with spicules, so as to 

 resemble a textile fabric (PI. XI I. tig. 9, a). Pores and vents 

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

 in the hi.stodermal forms, the structure is so delicate that all 

 the soft j)arts are broken down into a confused pulp. Internal 

 structure (fig. 9, b) 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 teiininate 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 niierospined, 27- by 1-1 800th inch 

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

 acuatc, smooth and pointed, subundulous, 32-oo-6000ths by 1- 

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

 1, ver}- small, equiauchorate, navicular, 3-GOOOths inch long 

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

 pointed, 30-GOOOths inch long (fig. 9, d). Tlie 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. 



Jfah. ^larine, 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. " 65," which 

 gives the locality and depth alx)ve mentioned. One is accom- 

 panied by a fragment of Ilnlirhondria 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 one" have a tendency to an aniatp 



Ann. d' Matj. X. Tlii^t. Ser. 4. Vol. xviii. 21 



