18 Mr. 11. J. Carter on two neiv Species of Gumminese. 



deep-sea one, together with observations on the Gunimine^ 

 generally. 



For the deep-sea specimen I would propose the name of 

 " Cortkium abyssi,''' and for the one from Port Jackson " Chon- 

 drilla australiensis^'' giving my reasons for adopting these 

 names hereafter. 



Corticium ahyssi, n. sp. (PL I. figs. 1-9 & 15.) 



Repent, amorphous, assuming more or less the form of the 

 object or cavity in which it may be growing. Smooth, slippery, 

 of a light greyish-yellow colour ; scmielastic, subcartilaginous, 

 solid. Tearing when wet like hard-boiled white of ^gg^ but 

 much tougher; brittle when dry, and breaking like glass. 

 SpiciilifcrouSjbut not fibrous in the sense of spongologists — that 

 is, without fibrous skeleton. Aspect homogeneous, massive, 

 })uckered here and there on the surface towards fixed points as 

 if from contraction or forcible extension. Vents numerous, 

 small, of different sizes, congregated here and there irregularly 

 (figs. 1 & 2, c). Pores microscojHC, linear, more or less uni- 

 formly spread over the surface (fig. 9, h). Internal structure 

 fleshy, solid, composed of an opaque mass or body of ovoid 

 cells, surrounded by a thin, translucent cortical rind ; per- 

 meated throughout by branched systems of excretory canals, 

 respectively terminating in the vents mentioned, and charged 

 with siliceous spicules most numerous at the circumference. 

 Microscojnc structure : Surface consisting of a thin, tough, 

 transparent cuticula, composed of parallel fibres, supported on 

 the points of spicules, in the intervals between which are the 

 pores ; covering the cortical substance beneath, which consists 

 of a layer of spicules imbedded in a kind of trama composed of 

 fine fibres and minute granuliferous cells. Trama of the 

 cortex soon rendered opaque by the presence of the body of ovoid 

 cells, to which it affords respectively separate cavities of a 

 similar shape throughout the mass. Ovoid cell about 5-6000ths 

 inch long, filled with granules, in which there appears some- 

 times to be a faint trace of a nuclear body; maintaining its form 

 when out of Hs cavity, but presenting no appearance of cell- 

 wall (fig. 8, a). Surface of the excretory canals covered with 

 an epithelium of small conical cells, whose free ends, projecting 

 above the level of the canal, form, in juxtaposition, a remark- 

 ably rough granular pavement, which appears to be not less 

 connnon to the mouths of the pores and their canals than to 

 the excretory system generally (figs. 15 & 9, Z^). Mode of ter- 

 mination inwards of the pore-canals and commencement of the 

 excretory ones not observed. Spicules of two kinds, viz. bi- 



