Classification of the Sponyida. 139 



Group 13. Incrustata. 



Sarcode ? (absent.) Skeleton composed of a reticulation of 

 horny anastomosing fibre, cored with minute foreign objects 

 and incrusted with the same. Fibre of two kinds — viz. vertical 

 or large, and horizontal or small. Surface ? (worn away.) 

 Structure vertical, radiating, or plumose. Texture open, resi- 

 lient. Forms massive and lobed, or flat and palmate. 



Group 14. Otahitica. 



Sarcode colourless, yellowish, or purple throughout. Skele- 

 ton composed of a reticulation of horny, short-jointed, anasto- 

 mosing fibre, colourless, pale yellow, or purple ; more or less 

 covered with minute foreign objects, chiefly towards the surface. 

 Fibre of two kinds — viz. vertical or large, and horizontal or 

 small ; the former chiefly cored towards the surface, where, by 

 anastomosing with the latter, it ends in a minutely reticulated 

 and granulated even plane, more or less divided by furrowed 

 reticulation. Structure vertical reticulate. Texture more or less 

 hard and compact. Forms incrusting, massive lobed, branched 

 lobed anastomosing, branches round or compressed ; or 

 flattened generally, open and flabelliform or closed and vasi- 

 form ; leafy, exfoliate or proliferous*. 



Group 15. Sarcocornea. 



Sarcode? (absent.) Skeleton composed of a reticulation of 

 sarcocornean or sub-horny anastomosing fibre of a pale yellow 

 colour, more or less cored with minute foreign objects. Fibre 

 of two kinds — viz. vertical or large, and horizontal or small ; 

 the former terminating on the surface in subaculeations, 

 which are united by reticulation into meandriniform ridges or 

 polygonal subdivisions presenting a uniform even character. 

 Structure reticulate. Texture firm, compact. Forms massive 

 lobed. 



Group 16. Arenosa. 



Sarcode colourless throughout or purplish on the surface. 

 Skeleton composed of minute foreign objects, formed by the 

 aid of a thin film of sarcode into a fibrous reticulation, of a pale 



* N.B. This group, based upon Ellis's Spongia othaitica, may afford 

 forms in which a core of foreign bodies in the fibre seems to be entirely 

 absent, as in Esper's Sp. papi/racea, Taf. 65,=Sponffio>iella Holdsworthii, 

 Bk. (Proc. Zool. Soc. 1873, pi. v.), thus bearing the same relation to the 

 typical structure of Sp. othaitica that the Bibulida bear to " Hircinida ;" 

 while among the Cavochalinida we have still another similarly flattened 

 form where the horny fibre is cored with a proper spicules." 



