Sponges from South Australia. 119 



20. Suherites parasitica. 



This consists of a thin layer of small pin-like spicules 

 about 40 by l-GOOOtli in., together with others of ? HiUchon- 

 dria panicea about twice the length, parasitically covering a 

 fucus [Thamnoclonium flahelUforme, Harvey, Frecmantle. 

 See 'Annals,' 1878, vol. ii. p. 162 &c., "Parasites on the 

 Spongicla "). 



Group 13. PoLYMASTiNA (new group) . 



21. Polymastia hicolor. 



Massive, flattish, sliglitly convex, circular, sessile, bossed 

 wilh slightly convex circular kaobs of a dark grey-brown 

 colour, set as it were in a yellowish flat mass ; " bosses " 

 varying in diameter under | in. Consistence hard, firm. 

 Colour when fresh " dark grey-brown," now, as just men- 

 tioned. Surface dermally smooth, especially over the dark 

 projecting portions or " bosses." Vents lateral and towards 

 the base. Spicules of one form only, but of two sizes, 

 according to their position: — 1, skeletal, subpin-like, varying 

 to simple acuate, 150 by 2^-6000ths in. ; 2, the same, but 

 much smaller, viz. 10 to 20-6000ths long ; the former radia- 

 ting in bundles from the interior to mingle their points with 

 a layer of the latter, which are confined to the surface. Struc- 

 ture consistins; from without inwards of an areniferous dermal 

 layer of a yellow colour, followed by a tough compact basal 

 tissue composed of radiating bundles of the large spicule 

 traversing a yellow sarcode and extending in a diminishing 

 degree, core- like, through the centre of the bosses, where its 

 presence at the summit can just be distinguished; bosses 

 otherwise composed of the same radiating kind of spicular 

 structure, but in a dark grey sarcode, which makes the differ- 

 ence on the surface that led to the designation " hicolor.''^ 

 Excretory canal-systems traversing the whole in such a pecu- 

 liar form that it will be desirable to describe this particularly 

 in the " Observations." Size 1^ in. high by 3 x 4^ hori- 

 zontally. 



Depth 7 fath. 



22. Polymastia hicolor j var. glomerata. 



The same, but with the bosses enlarged and elongated so 

 as to obscure the yellow basal structure beneath, and thus 

 only present a conglomeration of mamilliform processes. 



