PORIFERA. I. 51 



of which the stalk is 30™'", the greatest breadth is 10'"'", and the diameter of the oscular canal is a 

 few millimetres. The consistenc\- is soft; the surface is finely shaggy from the projecting spicules, 

 and the colour (in spirit) is light gra>ish yellow. The dcrvial membrane is thin, transparent, without 

 spicules, and is pierced by the ends of the fibres. 



The skeleton is unispicular (not formed by bundles of needles, as stated by Armaiier Hansen), 

 and consists of primary fibres running regularly upward and arcuately outsvard towards the surface, 

 and of spicules placed at right angles to these fibres, but forming themselves no distinct fibres; besides 

 some thicker, poh'spicular fibres run from the stalk iip through the sponge. In the nodes the spi- 

 cules are imited b}' a clear mass of spongin. 



Spictila are slender oxea, rather sharply curved in the middle, of a length of 0-22 — 0-238"'"', and 

 a thickness of 0-009 — o-oio"""; they are of equal thickness through their whole length, and have a 

 rather short, but ver\- .sharp point. 



This species, as will be seen, has spicules of a similar size as those in R. parenchyma; they 

 may, however, easily be distinguished from the spicules of this latter species, partly by their being 

 more sharply curved, and especially by their ends, the point being bounded by curved lines, while in 

 parenchyma it is longer and bounded by straight lines. The species is allied to clavata, but may be 

 distinguished from this species by its thinner and more curved spicules. 



Locality: The species was taken by the Norwegian North-Atlantic Expedition on station 255, 

 Vestfjord, 68' 12' Lat. N., 15' 40' Long. W., depth 341 fathoms; two specimens. 



Remarks: This species is the only Reiiiera-s^&ci&s taken by the Norwegian North-Atlantic 

 Expedition, oblonga and velamejitosa, as has been .shown above, being /falichondr/'a-species, while tud/t- 

 losa, mcmbranacea, nivea, and inflata belong in quite other places, and the rest are AxineUids. 



Note. Vanhoffen, in the work quoted before, p. 248, enumerates a Pachychalina oblonga Arm. 

 Hans., which, to judge by a preparation sent to me, is no Pachychalina, nor Halichondria oblonga Arm. 

 Hans., but a i?r«z>ra-species; it is impossible to determine the species after the preparation in hand, 

 as the skeletal structure cannot be seen. To judge b\- the spicules the species might possibly be 

 R. ve.ntilabriim, but the outer form is b)- \'anhoffen stated to be quite different from that of this 

 species. 



The Reniera-s-pftcies described in the foregoing, divide into two groups: forms with unispicular 

 skeleton, and forms with polyspicular skeleton. All the forms with the regular unispicular skeleton, 

 as far as the\- are erect forms, have, besides this regular skeleton, a greater or smaller number of 

 polyspicular fibres issuing from the base, where they are thickest and closely gathered, and from 

 where thev branch up through the sponge in a more or less regular manner, and without an\- decided 

 relation to the other skeleton. This reminds of the fact described by Top sent by the establishing of 

 the genus Cladocroce with the species fibrosa (Resultats des campagnes scientifiques du Prince de 

 Monaco, Fasc. H, 72, PI. HI, Fig. 1—2), and the other description of the structure of this species seems 

 also to agree with the structure of the lameUiform species described in the present work. Topsent, 



7* 



