1881.] THE SURVEY OP H. M.S. 'ALERT.' 119 



of that genus are settled, it will be well to adhere to the more com- 

 prehensive term Esperia for these forms. 



The nearest allies of this Sponge, of which intelligible descriptions 

 or specimens are available, appear to be : — 



Spinulaie spicule. nequi- Accratcs, 



Esperia wot^osa, Schmidt, "I '4117 by •011085 -0577 mm. •057 mm. 



Adr. Meer. Suppl. i. p. 33 J mm. 



(Adriatic). 



E. bowerbanki, id. Adr. l About same as •06334 mm. Ditto. 



Meei'. p. 55 (Adriatic) ... J preceding. 



£■. ;';<«/c«?'«,id. ibid.(Adri- 1 onn i, nnd- a-oo rv^^-f: 



j^j-jg-v ^ ,'• '399 by -0090 mm. -00384 mm. -0475 ram. 



-E". rhopalophora and E. intermedia, Schmidt, from the North 

 Atlantic, may perhaps prove, when more fully described, to come 

 near this species. Rhaphidotheca affinis, Carter, from oiF the north 

 of Scotland, differs but slightly from it in the forms of its spicules ; 

 but their sizes are greater. 



For details of appearance in life see Dr. Cunningham's work on 

 the Straits of Magellan above mentioned. 



•^n^ 



Alebion proximum, sp. n. (Plate X. fig. 8.) 



Incrusting. Surface covered with numerous narrow convolutions, 

 aud minutely roughened ; vents scattered, '2 to •S millim. in dia- 

 m^eter. Colour dark brown. Main skeleton composed of primary 

 columns of spiculo- fibre running from base towards surface ; fibres 5 

 to 6 spicules thick, crossed by secondary bars approximately at right 

 angles, bars 2 to 5 spicules thick. Dermal skeleton a regular poly- 

 gonal network of spiculo-fibre, 1 to 5 spicules thick, beneath which 

 lie irregular tracts of cylindrical spicules. Spicules united in fibres 

 by a minimum of sarcode. Parenchyma very granular, reddish 

 brown. Skeleton-spicules of two kinds : — (i) acuate, covered from base 

 to apex with short spines, tapering from within about 5 diameters of 

 apex to a sharp point, size "ISSSS by '0095 millim., in main and der- 

 mal skeleton ; (ii) cylindrical, tapering from middle to a neck, termi- 

 nated by a distinctly spined head, at each end, size -15835 by "0079 

 millim., in subdermal tracts. Flesh-spicules of two kinds : — (i) inequi- 

 anchorate, upper palm conical in outline, inferior edges angulated, 

 shaft slender, lower palm small, triangular, terminated by a sharp 

 point, length '02534 millim., scattered ; (ii.) bipociilate, exactly 

 similar to that of the British species Halichondria hyndmani, 

 Bowerbank, size "OlOoG millim. broad (from back of shaft to front 

 of the curves), scattered. 



Examined. In spirit and by mounting in balsam. 



External Characters. This species is represented by a specimen 

 coating one valve of a Pee ten. It resembles Halichondria hyndmani 

 and other nearly allied British forms in its corrugated surface. At 

 the centre of the shell it is merely a brown film. The convolutions 

 are sometimes substellately arranged, and may be as much as 



