SPONGES FEOM THE WESTEEN COAST OF NOETH AMEEICA. 117 



Two specimens of this species, rather small in size, but showing the typical pore-areas 

 or "cracks," were collected in Behring Sea. This sponge is now known to be circumpolar 

 in its distribution. Fristedt has described a new variety ' of Esperella lingua from Behring 

 Sea, but does not state in what respect his variety diflfers from the type specimen ; no 

 mention is made of the localization of the pores, which is the chief characteristic o? Esperella 

 lingua, Bow. 



Locality. — Bay of Islands, Adak Island. 



Esperella helios, Fristedt. 



(Plate II., figs. 4, 4 a— c.) 



Esperia helios, Fristedt. 18S7. Sponges from the Atlantic and Arctic Oceans and tlie Behring Sea (translation), 

 Vega-expeditionens vetenskapliga arbeten, p. 450, pi. 25, figs. 25-29. 



This sponge is found attached to shells, sea-weed, etc., or growing freely, forming sub- 

 spherieal or flattened masses of moderate size. There are four specimens, the two largest 

 of which are about 40 mm. across by about 25 mm. high. Colour, a light yellowish-ln-own. 

 Texture, firm. Surface, hispid, roughened by numerous small protuberances. Dermal 

 membrane, very thiu and fragile. Pores, scattered, about 0-111 in diameter. Oscula, dis- 

 persed, generally small but often of considerable size, communicating with the interior of 

 the sponge by a number of canals. 



Skeleton. — Well defined main fibres of spicules run to the surface, where they become 

 diftuse without the formation of definite brushes. Secondary fibres are feebly developed 

 in places, otherwise they are represented b}- individual spicules which cross the primarj' 

 fibres at right angles, connecting them together, or by spicules occurring without order 

 between the primary fibres. The hispidity of the surface is caused by the slight projection 

 of the s[iicules of the outer ends of the primary fibres beyond the dermal membrane. The 

 surface protuberances are aggregations of spicules, arranged in a plumose manner, which 

 rise from one to two mm. above the general surface of the sponge ; they are formed by the 

 union of two or more primary fibres which form an indefinite central axis from which 

 spicules radiate outward and upward. There is only a small proportion of spongin present 

 in the skeleton. 



Spicules. — (a) 3fegasclera ; of one kind only, viz., stout, sharply and rather abruptly 

 pointed smooth styli (Plate II., fig. 4), often somewhat curved, from 0-327 to 0-438 mm. 

 long and about 0-018 mm. thick, (b) Microsclera : (1) palmate anisochelse (Plate II., figs. 

 4a, 4b), occurring in beautiful rosettes of from ten to thirty spicules, in the dermal mem- 

 brane and scattered separately throughout the skeleton ; average length 0-058 mm. 

 (2) Sigmata (Plate II., fig. 4c), slender, simple and contort, abundant in the dermal 

 membrane and throughout the sponge generally. 



Distribution. — Arctic Ocean, Behring Strait and Behring Sea. 



Esperella adherens, Lambe. 

 (Plate IL, figs. 5, 5a— f.) 

 Egptrella adhaerens, Lambe. 1893. Trans. Koyal See. Canada, vol. xi., p. 27, pi. ii., figs. 5, 5a — d. 



1 Experdla lingua. Bow. var Arctica, Fristedt, 1877. Sponges from the Atlantic and Arcfc Oceans and Behring 

 Sea (translation), Vega-expeditionens vetenskapliga arbeten, p. 449, pi. 25, figs. 20-24, pi. 29, fig. 18. 



