r PORIFERA. I. 



Geogr. distr. Fristedt mentions the species from Spitzbergen, on a depth of 15—25 fathoms. 

 The species seems to be found exclusively in more shallow water. 



We have a fragnnent, a tube of a length of 11™™ and a breadth of 4""", from Iceland, Breida- 

 sound, depth 30 fathoms (H. Jonsson). It has a polyspicular skeleton constructed as that of tiibulosa, 

 and the spicules have a similar form, most frequently with a more or less sharp curve, but they are 

 somewhat smaller, the length is ca. 0-15""", and the average thickness 0-0057'""'. 



Note. Reniera tubitlosa Arm. Hans. The Norwegian North-Atlantic Expedition XIII, 4, 1885, 

 will have to be dropped, as it is identical with Occanapia robusta Bow. (see under this species). 



9. R. laxa n. sp. 



PI. II, Fig. 6, PI. XI, Fig. 13. 

 The form is the typical our: from an extended^ more or less criisf-shaprd hasr more or fnvrr 

 cylindric or conical, somctiiius somc7v/ial compressed osczdar tubes rise, which may nozu and then be 

 coalesced. The dermal membrane is thin. witho7il spicules, the ends of the fibres project, and so the 

 surface is finely shaggy. Oscnla are found on the fop of the oscular cones. The skeleton is a so?)ie7vhal 

 irregular network of polyspicular fibres running tozuards the surface, and single transverse spicules, con- 

 necting the former. Spicula are evenly tapering, slightly curved oxea of a length from o-i8 — o-2o8""''. 



The specimens in hand of this species grow on Br^ozoa, Balanoids, etc. More or fewer cylin- 

 dric or fusiform tubes rise from the base; they are rather low, and may be more or less coalesced, 

 and sometimes they are a little compressed. The largest specimen has a length of 60-"'", and a greatest 

 height of 30™™. The smallest specimen, which is presumably quite young, is of an almost semiglobular 

 form with an osculum on the top of it. It has at the base a diameter of 12""", and a height of S™™; 

 its oscular canal is very short, and leads almost directly into the excurrent canals. The consistency is 

 very loose and soft, and the sponge is therefore very fragile and little coherent. The colour (in spirit) 

 is whitish or slightly yellowish, and the surface has the common netlike appearance. The surface is 

 finely shaggy from the projecting spicules. The dermal membrane is thin, transparent, and without 

 spicules or special dermal skeleton; it rests on the skeleton below, and is pierced by the ends of the 

 fibres. The pores are found in the dermal membrane, and especially on the tubes they are exceedingly 

 close-set, so that the skin here becomes a sieve; in the other parts of the surface of the sponge the>- 

 seem to be much more spread ; they are somewhat varying in size, and are measured to 0-017 — 0-089"^". 

 Oscula are found on the summit of the tubes, and have a diameter of ca. 2 — 4™"; they have a rather 

 sharp edge; from the osculum an oscular canal of the same width leads down through the tube, and 

 the inside of the tube is in the general wa}- provided with openings for the excurrent canals; below 

 it passes into the system of canals. 



The slieleton is chiefly constructed as in tuhUosa. Polyspicular fibres run towards the surface 

 and in the oscular tubes upward and arcuately towards the surface; they are somewhat varying in 

 thickness and in the number of spicules, but the number seems most frequently to be about 3 — 6 

 spicules alongside. The distance between these primary fibres is generally of the length of a spicule; 

 the spicules running perpendicularly on the former, form no distinct fibres, and they are most frequently 



