PORIKKRA. II. 



103 



1885. Desmacidon nucleus Armauer Hansen, ibid. PI. Ill, fig. 1, PL VI, fig. 17. 



1885. Desmacidon gigantcum Armauer Hansen, ibid. PL II, figs. 12, 13, PL VII, fig. 8. 



1885. Desmacidon arcticum Armauer Hansen, ibid. 15, PL VI, fig. 16. 



1887. Cladorhisa nobilis Fristedt, Vega-Exp. vetensk. Iakttag. IV, 456, PL 25, figs. 60—65, PI- 3 1 ) &g- 2 ^>- 



Erect, club-shaped, on the upper part with a number of short, papillose branches swollen towards 

 the point: below the axis is dissolved to a branched root. A layer coating the stalk and root and pro- 

 vided with special spicules present. The skeleton af the generic type, consisting of a powerful, below 

 spirally twisted spicula-axis through the middle of the sponge, and thin spicula-axes in the papilla. 

 Spicu/a: Megasclera styli of two sizes, long ones in the axes, 1-2—2""", shorter ones in the other parts 

 of the body 0-36 — 7-2"""; finely spinulous styli in the layer coating the stalk ir/rS'—o-jp"'"; microsclera 

 of three forms, isancorce unguiferce of two forms, large ones with six teeth 0-037— 0-077""", small ones 

 with six to nine teeth croiS — o-oj""". sigmata with compressed terminal parts 0-037 — 0-043""". 



This beautiful and interesting species reaches a considerable size, as has already been expressed 

 by Armauer Hansen in the specific name, although his specimen had only half the length of the 

 largest specimen before me. The species consists of a stem, dividing below, first into rather thick 

 branches, then by and by into thinner ones, so that a rather richly branched root is formed. The 

 stem continues upwards, and increases in thickness in its upper half, so that the sponge becomes about 

 club-shaped. The upper, thicker part is set with a great number of papillae, not regularly arranged. 

 The papillae have a broadly conical base passing into a thinner stalk which again ends in a more or 

 less swollen head. The papillae may otherwise be somewhat different in length and form, the length 

 of the stalk may be different, and the end may have a more or less marked head-like swelling. The 

 papillae may also be somewhat differently directed; in the specimens in hand most of them are more 

 or less turned downwards, only the uppermost ones are directed upwards. Up to where the lowermost 

 papillae begin, the root and stalk is coated with a layer provided with special spicules and of the 

 same character as that found in several Asbcstopluma-species; the layer is here very thin, and it is 

 highly filled with mud, so that it must be supposed that the sponge has been sunk in the bottom so 

 far as the layer reaches. The largest specimen in hand has a height of 43 cm , of which the stalk and 

 root make about the half part; the stalk is ca. 2i mm thick, and the greatest thickness above is 55""". 

 The length of the papillae inclusive of the conical base cannot be given exactly, but it does not 

 exceed 25"™, and in their thinnest stalk-shaped part they have a thickness of 3 — 5 mm . Armauer 

 Hansen's specimen was 22 cm high, and two smaller specimens before me are ca. i5 cm high, the other 

 measures being in proportion to this. The colour (in spirit) is yellowish white; the lower part, which 

 is covered by the coating layer, is, on account of the mud in it, dark gray, which colour ceases with 

 a sharp boundary line. On account of the axial skeleton the sponge is firm and stiff, and the layer 

 has outermost a rather hard, crusty consistency, but it is inelastic and somewhat brittle. The outer 

 crusty tissue is not sharply bounded inward, but passes more or less evenly into the inner, softer 

 tissue. The surface is apparently smooth, but under a magnifying glass it is seen to be finely shaggy. 

 The outer crusty layer may rather easily be peeled off, while the outermost membrane, the dermal 

 membrane proper, may be distinguished, but cannot, or only with difficulty, be isolated. Pores may be 



