22 



E. ARNESEN. 



[REP. OF THE "MICHAEL SARS" NORTH 



larger ones are in the fibres, while the smaller ones 

 project from the fibres and are scattered between them. 

 2) Fusiform tylostyli, smooth, straight or somewhat 

 curved, with a round markedly constricted head and sharply 

 pointed, usually varying in length from 0.111—0.148 mm, 

 with a thickness of 0.0037 — 0.0148; they are scattered and 

 not exceedingly abundant. 3) Very slender, smooth 

 subtylostyti or tylostyli, with an oval not markedly con- 

 stricted head and not always sharply pointed. They vary 

 much in size, 0.185 — 0.407 mm., and are scattered through- 

 out the sponge. In the dermal membrane they are 

 the only megascleres present and form there a dense 

 felt, in which the spicules are arranged parallelly to, the 

 surface. Single, very thick strongyl-tornote spicules, 

 apparently abnormalities, have also been observed. The 

 microsclera are small palmate isochelce, 0.0222 mm. 

 long, not very abundant, but scattered all over the sponge. 

 There have also been observed in abundance smooth, 

 not much curved, toxa, ordinarily with the opening of 

 the curvature about 0.166 mm.; at first I thought they 

 belonged to a foreign sponge, (there being many foreign 

 bodies and spicules present), but they are so regularly 

 distributed throughout the whole sponge, that I must 

 believe they belong to it. 



Exept the presence of the toxa this sponge in all 

 other respects corresponds perfectly well with the genus 

 Eehinoclathria Carter. I therefore provisionally at least 

 refer it hereto leaving to a closer examination of this 

 genus, the diagnosis of which only is a prelimary one 

 (Ridley and Dendy op. cit, p. 160), to decide whether 

 the toxa really belong to it or not. 



The species to which it makes the nearest approach 

 are undoubtedly Ech. carteri R. & D and Ech. favus 

 Carter. But as the specific diagnoses of these two species 

 are indefinite, and they may according to Ridley and 

 Dendy ultimately prove to be connected with intermediate 

 forms, I think it most convenient provisionally at least to 

 regard the "Michael Sars" species as distinct especially 

 on account of the different habitats — the earlier known 

 species being from the south coast of Australia, while the 

 "Michael Sars" material is from the north-atlantic coast 

 of Africa. Both agree in having been recorded from 

 rather shallow water — the „Challenger"-rnaterial being from 

 within a bathymetrical range of 30 — 120 meters and that 

 of "Michael Sars" from 37 meter depth. 



Locality: Between Gran Canaria and Cape Bojador 

 (Lat. 26° 6' N, long 14° 33' W); depth 39 metres; bottom 

 shingle; temperature 15.63 C. 



Anchinoe Gray. 



Syn: Stytistkhon Topsent. 



Vide litter: 34, p. 111. 



In the letter from Mr. Topsent previously mentioned 

 he remarks that in a paper about to be published: 



„Sur les Eponges des Mers da Nord prises par le 

 Prince de Monaco", he now regards his genus Styli- 

 st! ch o n, established in 1892, as a synonym of Gray's 

 genus Anchinoe; in this genus he includes Ridley and 

 Dendy's species of Myxilla, which have a skeleton 

 composed of fibres with echinating spicules. Accordingly 

 the species under consideration, with which I have identified 

 one specimen from station 37, must be called Anchinoe 

 nobilis (Ridley and Dendy). 



Anchinoe nobilis (Ridley and Dendy). 



Syn: Myxilla nobilis Ridley and Dendy (21, p. 140). 



PI. II, fig. 6. 



St. 37. One specimen. 



Sponge erect, of a somewhat flattened oval shape 

 with conical digitate processes. Base of insertion not very 

 broad. Texture rather tough. Colour in spirit mouse-grey. 

 Surface uneven, but not hispid. The dermal membrane 

 is translucent, thin, and may easily be peeled of. The 

 most remarkable feature of the surface are the densely 

 placed circular or oval areas, 1 — 2 mm. in diameter, 

 bounded by a distinct, minutely granular ring. They are 

 pore-areas, in some of which the openings of the subder- 

 mal cavities are to be seen with the naked eye. Oscula 

 are small and scattered, their margin flush with the sur- 

 face, or a little sunken. 



Skeleton. The dermal skeleton consists of stron- 

 gyla arranged in penicillate, erect or somewhat recum- 

 bent, bundles supporting the dermal membrane. They are 

 especially localised round the poreareas, where they form 

 a dense palissade bending over the subdermal cavities, here 

 projecting above the surface with their distal ends and 

 forming the minutely granular rings previously mentioned. 

 The spaces of the membrane between the pore-areas have 

 usually only isancorae and a very few isolated horizontal 

 strongyla. 



Spiculation. 1) Acanthostyli verging upon 

 acanthotylostyli, straight or usually slightly curved, 

 0.59 mm. long and 0.019 mm. thick, gradually tapering 

 towards the apex. The sharp spines are not very close- 

 set except at the base. 2) Smaller acanthostyli, verging 

 upon tylostyli, 0,222 mm. long and 0.007—0.015 mm. 

 thick, usually straight and gradually tapering towards the 

 apex. They are covered by long and sharp closely set 

 spines, especially at the base. 3) Strongyla, smooth 

 usually straight, 0.407 mm. long and 0.0074 mm. thick. 

 They are, all very uniform typical strongyla, except that 

 occasionally they show a tendency towards an abrupt 

 truncation with a faint spinulation at the one end, as in 

 Myxilla nobilis R. & D, (fig. 14 & fig. 15, pi. XXVII, p. 140 

 op. cit). Microsclera are isancorsespatuliferce with 3 

 teeth and a rather curved shaft, 0.044 mm. long and 

 0.0074 mm. thick. 



