REPORT ON THE MONAXONIDA. IdS 



JEchinodictyum rugosum, Ridley and Dendy (PI. XXXII. figs. 1, la). 



1886. Echinodictijum rugosum, Ridley and Dendy, Ann. and Mag. Nat. Hist, ser. 5, vol. xviii. p. 477. 



Sponge (PL XXXII. fig. l) stipitate, palmato-digitate, consisting of a sliort cylindrical 

 stem about 19 mm. long, surmounted by a broad, flattened expansion which terminates 

 in a series of flattened, digitate processes. Total height of specimen 187 mm., greatest 

 breadth 131 mm.; thickness only about 4 mm. (the stalk is a little thicker). Colour 

 in spirit greyish-yellow. Texture hard and rather brittle. Surface rugose, thickly beset 

 with small, pointed eminences. Oscula and pores unknown. 



Skeleton. — A well-developed, compact, but rather iiTegular reticulation of strong 

 spiculo-fibre ; the fibre consisting of a multispicular axis of smooth oxeote spicules, firmly 

 united together, and very abundantly echinated by spiued stylote spicules which project 

 from it approximately at right angles. 



Spicules. — Megasclera; of two kinds. (1) Smooth oxea, somewhat hastately 

 pointed and usually bent at an angle in the centre, size about 0"3 by 0'015 mm., in the 

 skeleton fibre. (2) Entirely spined styli (subtylostyli), tapering gradually to a fine but 

 not very sharp point and with the spines most abundant on the base; size about 0"13 

 by 0"012 mm., abundantly echinating the skeleton fibre. 



This species difi"ers from aU other described members of its genus in its palmate, slightly 

 branched form ; Echinodictyum nervosum, Ridley,^ which also grows in one plane, being 

 ramose from the stem upwards, and Echinodictyum cancellatum, Ridley,^ forming a can- 

 cellate growth in a single plane. 



Locality.— Station 190, September 12, 1874; lat. 8° 56' S., long. 136' 5' E.; south- 

 west of New Guinea; depth, 49 fathoms; bottom, green mud. One specimen. 



Echinodictyum asperum, Ridley and Dendy (PL XXXII. fig. 2). 



1886. Echinodictijum asperum, Hidley and Dendy, Ann. and Mag. Nat. Hist., ser. 5, vol. xviii. p. 477. 



Externally this species (PL XXXII. fig. 2) has very much the appearance of a so-called 

 Keratose sponge. It is bushy and of suberect growth, cavernous and covered with large 

 aculeations ; most of the specimens are attached to fragments of coarse rock or Coral. Height 

 commonly about 50 mm.; breadth about the same or a little more. Colour in spirit rich 

 chocolate brown.^ Texture coarsely fibrous. Swface uneven in the extreme, but 

 glabrous where the dermal membrane is intact. Dermal membrane thin and transparent, 

 containing an enormous quantity of reddish brown pigment granules disposed in small 

 groups. This pigment is still more abundant in the deeper parts of the sponge. 



1 Journ. Linn. Soc. Land. (Zool.), vol. xv. p. 496, pi. xxviii. flgs. 7-10. 



2 Zool. Coll. H.M.S. "Alert," Brit. Mus., 1884, p. 457, pi. xl. fig. D. 



^ Evidently natural, as otlier sponges attached are not coloured like this. 



