C^,, PORIKERA. I. 



and by a closer examination it is seen to be sli<^htl\' and sparingly spinnlons from sinjjly placed, 

 slio-hth- projecting spicnles. On acconnt of the close-set spicules, the external part of the sponge, which 

 is marked off as a dermal lnvir, is \ery firm and hard. I have not observed pons in the exceedingly 

 close-spiculed skin. Oscit/a : In one specimen, in which two fistnlte are found that are likely to be 

 whole, these fistuke are open at the summit, and the openings must be taken to be oscula. One fi- 

 stula has the opening at the ver}- top, while in the other the opening is in the side just below the top. 

 The 'skelrton. As has been mentioned, the species has outermost a part formed as a dermal 

 la\-er; this dermal layer is very hard, and provided with exeedingly close-set spicules l)ing in several 

 layers; the dermal layer has a thickness of somewhat more than o-i'"'". The spicules of this layer are 

 parallel to the surface, and their arrangement, as the curved spicules form angles with each other, 

 shows a pattern recalling the kind of engraving frequent on the back of watches, the so-called guil- 

 loche. The spicules, to be sure, are chiefh- parallel to the surface, but at certain intervals the whole 

 la^■er of spicules rises into low, conical processes, through the midst of which a spicule projects a little, 

 so that the surface is slightly spinnlons. The skeleton in the soft interior of the sponge, as far as I 

 have been able to decide from the material in hand, consists of spicules lying scattered in the tissue 

 without an>- order, and without forming any reticulation or fibres; neither seem, as in the preceding 

 species, any lamellse to be found. On the other hand, the membrane lining, at all events the larger 

 canals, is provided with a spiculation of about the same kind as that of the dermal la\er, but conside- 

 rabh- more open, so that a kind of network is formed. In the inner body no spongin is observed in 

 the skeleton; on the other hand spongin is found uniting the spicules of the dermal layer and of the 

 membranes; the spongin is exceedingh- white and clear, and consequently not easily seen. As in the 

 preceding species, and to a still higher degree, a large number of extraneous bodies are also found in 

 the present one; in one specimen externally highly incrusted with sand, the sand is also found in the 

 interior together with sponge-needles; in the other specimen large sponge-needles are almost exclu- 

 sively found crossing the sponge in every direction. 

 \ Spic/ilti are comparati\-ely sliort and thick oxea, rather highh- bent; the bending may be even, 



<i> "« ■>\f^\ '^"t most freqnenth' it is rather sharp; the spicules are shorth- pointed with a rather stubby point, under 

 i. 9 '^ ni'l'>»i' higher magnifying powers the point shows outermost a little apex especially marked off. Sometimes, 

 ^'Sq ■^■''(^.- but rather rarely, the ends are romided; Topsent mentions this fact to be of frequent occurrence in his 



^^'0 V>^ specimens. The length of the oxea varies from o-i6 — 0-19""', the thickness from o-oi2— o-oi8""". Deve- 



lopmental forms, down to quite fine ones, occur, but in rather small numbers; the finest have a length 

 of 0-I4""". The fine needles are long tapering, and consequently the short point appears only during 

 the growth. 



Localitv: Station 78, 60" 37' Lat. N., 27° 52' Long. W., depth 799 fathom.s, one specimen; station 81, 

 61° 44' Lat. N., 27 00' Long. W., depth 485 fathoms, one .specimen. Both stations are situated a little 

 to the south of the Denmark Strait, station 81 on the Reykjanaes-ridge, station 78 on the eastward 

 slope of this ridge. 



(tcoor. distr. The species has been established on four specimens taken on the expedition of 

 the Prince of Monaco with THirondelle in 1888 at the Azores on a depth of about 138 fathoms 

 (Top.sent 1. c). 



