REPORT ON THE MONAXONIDA. 181 



Axinella profunda, Ridley and Dendy (PL XXXVIII. figs. 2, 3 ; PL XL. figs. 3, 3a). 

 1886. Axinella profunda, Ridley and Dendy, Ann. and Mag. Nat. Hist., er. 5, vol xviii. p. 480. 



Sponge (PL XXXVIIL fig. 2) smaH, erect, stipitate, dichotomously branched ; stem 

 and branclies slightly flattened in one and the same plane ; stem expanding below into 

 a small, woody base. Height of specimen 50 mm.; breadth of stem and branches about 

 4 mm. Colour in spirit yellowish-grey. Texture; there is a tough, woody axis 

 surrounded by a soft, spongy coat. Thin, membranous threads extend and form 

 connections between adjacent branches ; possibly we have here the first steps on the road 

 to complete anastomosis such as not infrequently occurs between adjacent branches of 

 ramose sponges. Surface fairly even where the dermal membrane is intact, hispid. 

 Dermal membrane thin and transparent. Oscula of moderate size, scattered. 



Skeleton. — There is a dense central axis of more or less longitudinally placed, large 

 stylote spicules, from which similar spicules radiate to the surface in tracts or brushes, 

 projecting beyond it and surrounded by bunches of smaller, slender styli whose apices 

 also project beyond the surface. 



Spicules. — Megasclera; of one form only, viz., styli (PL XL. figs. 3, 3a), straight, or 

 nearly so, and sharply pointed; ranging in size from about 0'55 by 0'0084 to about 2"0 

 by 0"037 mm.; the bases of the spicules, with few exceptions, are very minutely spined 

 (PL XL. fig. 3a). 



This description is taken from one specimen only (that from Station 241). A second 

 (PL XXXVIIL fig. 3), met with since it was written, confirms it in a very satisfactory 

 manner indeed, even down to the spination of the bases of the styli ; but it is of 

 a dark, reddish-brown colour. 



The most characteristic feature of the species is, perhaps, the incipient sijination of 

 the bases of the stylote spicules ; this, though very minute, is a perfectly definite feature ; 

 it is most noticeable in the smaller spicules. The species is especially interesting on 

 account of the very great depth and the widely distant localities from which it was 

 obtained. It would appear to be a widely spread species in abyssal regions of the 

 Pacific, maintaining its peculiar specific characters with singular constancy in very diff'erent 

 localities. 



Localities.— Station 241, June 23, 1875; lat. 35° 41' N., long. 157° 42' K; North 

 Pacific Ocean; depth, 2300 fathoms; bottom, red clay; bottom temperature, 35°-l. 

 One specimen. 



Station 281, October 6, 1875; lat. 22° 21' S., long. 150° 17' W.; South Pacific 

 Ocean; depth, 2385 fathoms; bottom, red clay; bottom temperature, 34°"9. One 

 specimen. 



