Explanation of PI. I?. 



Figs. 1, la. Spomjilla aspmona. 



Fig. 1. Skeleton-spicules. X300. 



Fig la. Microscleres. X30Ü. 



Figs. 2, 2a, 2b. Spongilla dementis. 



Fig. 2. Gemmules and skeleton-spicules. X50. 



Fig. 2a. Skeleton-spicules. X300. 



Fig. 2b. Gemmule-spicules. x30J. 



Figs 3, 3a, 3b, 3c Heterom.eyenia knivannrne. 



Fig. 3. Gemmule, x 70. 



Fig 3a. Skeleton-spicules. X300. 



Fig. 3b. Free microscleres. X300. 



Fig. 3c. Gemmule-spicules. x3,)0. 



