Spongillidae. 243 



Corimspongilla victoriae^ sp. uov. 



PL VI., Hgs. 4 and 5 A— C. 



Sponge: The sponge forms small lichenoid patches, often somewhat 

 densely congregated, on stones. Their outlines are irregulär, their diameter 

 not more than ab out 25 mm in the speeimens examined, and their thick- 

 ness inconsiderable. It is possible that at a later stage the different patches 

 may grow together to form a uniform layer. The texture of the sponge is 

 hard but moderately friable; its colour in dry speeimens yellowish, but 

 darker and browner in spirit. The pores and oscula are small and incon- 

 spicuous. 



Skeleton: The skeleton forms a dense reticiüation composed mainly 

 of Single spicules, the spicule-iibres are not well ditFerentiated falthough the 

 vertical fibres ean be detected as somewhat irregulär fascicles) and the 

 greatly thickened pillars of spicules characteristic of some species of the 

 genus are absent. 



Spicules (PI. VI, Fig. 5): The skeieton-spicules are relatively slender 

 amphistrongyli as a rule almost uniformly but by no means densely covered 

 with minute spines; occasionaUy these spines are almost absent. Not infre- 

 quently the extremities of the spicule are somewhat inflated. Rather shorter 

 and distinctly more slender amphioxous macroscleres also occur, but spa- 

 ringly and not incorporated in the skeleton. The free microscleres are of 

 two types, micramphidiscs and amphioxi. The former are of the usual form 

 and are not, in the speeimens examined, abundant. As a rule their discs 

 are formed of six long spines, which project outwards further than in some 

 species and are not recurved at the tips ; the shaft is never strongly curved. 

 The amphioxi, which are scarcer than the micramphidiscs, are slender and 

 nearly straight; they bear stout spines, which stand out straight at right 

 angles and are short at and near the extremities but often of considerable 

 length near the middle of the spicule. The gemmule-spicules are stout and 

 relatively short amphioxi, but exhibit great Variation in length and outline, 

 which is sometimes distorted and irregulär; they are uniformly and fairly 

 densely spined. 



Gemmule (PI. VI, Fig. 4): The gemmules are circular in outline and 

 dome-shaped externally, without an aperture of any kind. They adhere 

 Urmly at the base of the sponge. The outer coat consists of a single layer 

 of gemmule-spicules arranged horizontaUy and mosaic-wise in a stout chiti- 

 nous membrane more or less continuous with the basal membrane of the 

 sponge. Within this coat the inner capsule lies free. It has the form of a 

 narrow flask with a well-defined neck fthe forarainal tubule) and lies on 



