394 Mr. H. J. Carter on Deep-sea 



truncate obliquely above and horizontally below, the trun- 

 cated areas being circumscribed by a prominent ridge, which 

 above, when fully developed, rises into a circular wall that 

 terminates the head. Stem long, slender, expanded at first 

 where in connexion with the head, then narrow, and after- 

 wards gradually increasing towards the lower end, where it 

 suddenly thickens into an irregularly bulbous form, to ter- 

 minate in a bunch of numerous root-like fibres more or less 

 matted together with the sand in which the sponge has been 

 fixed. Colour grey. Surface hirsute throughout, hirsute- 

 ness especially evident over the head and ridges formed 

 by the pointed ends of projecting spicules, which, taking a 

 spiral direction round the body, end in a whorl for the most 

 part situated in the centre of the summit ; stem rugose or 

 corrugated circularly on the surface, where the rugaa are 

 most prominent at the lower part. Pores not seen. Vents 

 on the summit and upper part of the head respectively, con- 

 sisting of a large one in the centre of the whorl, and one to 

 five smaller ones along the projecting line formed by the 

 upper ridge, each vent prolonged by a little conical tuft of 

 spicules. Internal structure radiate, consisting of bundles of 

 large spicules imbedded in sarcode and issuing in gyrate lines 

 from a central point towards the circumference, where their 

 points intermingle with those of a dermal layer of small 

 spicules, which thus together produce the hirsute surface ; 

 traversed by the branches of the excretory canal-systems 

 which terminate at the vents mentioned. Stem internally 

 consisting of a gently spiral cord formed of large long spicules 

 applied longitudinally to each other successively, where they 

 are all held together by sarcode, and covered by a dense 

 dermal layer or sheath, through which the dermal spicules 

 project perpendicularly in the form of a minute crust. Spi- 

 cules of one form only and two sizes, viz. a body- and a 

 dermal-spicule. Body-spicule large, long, acerate, fusiform, 

 attenuatingly pointed at both ends, one of which is slightly 

 obtuse, nearly straight, 250- by 4-1800ths inch. Dermal 

 spicule of the same form, but only a 40th part of the length, 

 being 6-8- by -^-IBOOth inch. The body-spicule chiefly 

 belongs to the stem and bundles of the head, each of which is 

 faced by the layer of dermal spicules, while an intermediate 

 size filling up the interstices of the head causes the hirsute 

 character there to be more evident than on the stem, where 

 the dermal spicule alone exists. 



Size. This, like the form, depends upon age and tlie degree 

 of development. The largest I have is about 3^ inches long, 

 \ an inch of which is head and the rest stem ; the head is 

 about -fV ii^ch in diameter at its upper part. 



