PLATE VI. 



Cerelasma. 



Figs. 1-5. Cerelasma gyrosphzera, n. sp. (p. 46). 



Diam. 

 Fig. 1. A complete spherical specimen of the sponge, . . . nat. size 



Fig. 2. A small portion of a transverse section through a branch, f, spongin- 

 lamellse ; x, pseudo-skeleton composed of xenophya ; h, greenish 

 hydrorhiza of the symbiotic Hydroid, . . . x 50 



Fig. 3. A small portion of the section, fig. 2 ; more highly magnified. Char- 

 acters as in fig. 2 ; r, Radiolarian shells, . . . . x 300 



Fig. 4. Spongindamelke of the skeleton (f), without the imbedded xenophya, 



observed in glycerine, h, a forked tube of the hydrorhiza, . x 300 



Fig. 5. A single Eadiolarian shell, enclosed by a spongin-sheath ; from the 



edges of the sheath arise spongin-lamellse (/"), . . . x 300 



Figs. 6, 7. Cerelasma lamellosa, n. sp. (p. 47). 



Fig. 6. A portion of the sponge, with a partial section through the surface, . x 4 



Fig. 7. A small portion of a section through the sponge, f, spongin-lamelke ; 



x, xenophya (sponge spicules and mineral particles), . . x 300 



