PLATE IV. 



Psamm ophyllum. 

 Figs. 1-4. Psammophyllum annectens, n. sp. (p. 52). 



Diam. 



Fig. 1. A complete flabelliform specimen, . . . . . . nat. size 



Fig. 2. Portion of a section through the same, f, network of spongin- 



fibrillse ; r, Eadiolarian shells, . . . . x 300 



Fig. 3. Some spongin-flbrillse, including Eadiolarian shells, . . x 400 



Fig. 4. Chitinous tubes of the hydrorhiza of a symbiotic Hydroid, with annular 



constrictions (Eudendrium ?), . . . . x 100 



Figs. 5-8. Psammophyllum Jiustraceum, n. sp. (p. 51). 



Fig. 5. A complete flabelliform specimen, ..... nat. size 



Fig. 6. Portion of a section through the same, f, network of spongin- 



flbrillse ; r, Eadiolarian shells and sponge spicules, . x 300 



Fig. 7. Portion of the surface of fig. 5, from its distal part, exhibiting three 

 concentric zones, with the dermal pores (p), and the larger openings 

 (oscula, o) at the thickened proximal margin of each zone, . x 4 



Fig. 8. A small portion of the outermost distal zone ; more highly magnified. 



The surface exhibits the smaller openings (pores), and scattered 

 larger openings (oscula, o) at the thickened proximal margin of the 

 zone, . . ... . . . x 12 



Fig. 9. Halisiphonia spongicola, n. sp. (p. 77). 



Fig. 9. Hydroid living in symbiosis with Psammophyllum Jiustraceum. 



h, the reticular hydrorhiza ; g, gonangia ; p, hydrothecse, . x 20 



