i9o8.] 



Records of the Indian Museufii. 



27 



rule smooth but occasionally a little rough, variable in pro- 

 portions, probably slender and pointed when young. Gem- 

 mule spicules sausage-shaped, covered with short, straight 

 spines, which are sometimes absent from the extremities, vari- 

 able in length. Flesh spicules birotulate, usually occurring in 

 groups; their shafts smooth, slender, straight or curved, variable 

 in length ; their rotulse consisting of six or seven backwardly 

 curved spines. Gemmules congregated in groups at the base 

 of the sponge, oval or sausage-shaped, with a single depressed 

 aperture situated on one of the longer sides ; each gemmule 

 contained in an oval case of spicules and a dense chitinoid 



'^^'^ 



Fig. 3.^ — Gemmule of SpongiUa lapidosa in its case, the roof of which is 

 omitted, from below, x 30. 



substance, and having, apart from this, only an inner coat, in 

 which the spicules are embedded horizontally like a mosaic ; 

 the case consisting of an inner layer of skeleton spicules, occa- 

 sionally mixed with birotulate flesh spicules, and an outer one 

 formed of gemmule spicules massed together irregularly and 

 held in position bj' the chitinoid substance, the side walls of 

 each case being partly coincident with those of others. There 

 is a dense membrane at the base of l^ie sponge with wdiicli 

 the outer laver of the ijemmule cases is in continuity. 



Pig. 4. 



Fig. 5. 



Figs. 4 and 5. — SpongiUa lapidosa : lig. 4 = sausage-shaped gemmule, x 30; 

 fig« 5 = a group of spicules from the same, x 240. 



