Plate 7. 



Fig. 1, a, b, c. Farrca occa clavifonnls. Gastral clavulae with degenerate teeth; x 450. 



2. " " " Dermal pentact with clavulae ; x 250. 



3. " " " Gastral clavula; rare form ; x 450. 



4. Furrea mexlcana. Gastral anchorate clavula; x 450. 



5. " " " " " x460. 



6. Farrea occa claviformis. Gastral pentact with clavulae; x 250. 



7. Farrea mexicana. From a photograph ; |. 



8. " " Pentact with umbellate clavulae ; x 250. 



9. Eurete erectum tubuliferum. Part of surface view of sponge taken from the side. 



Axis of entire sponge about vertical. A com- 

 pletely bifurcated (tubular) lateral branch lies 

 to tlie right, showing a tubular ridge, which 

 marks the line along which the lips of the 

 earlier, cup-like branch fused. A similar 

 tubular ridge lies at right angles to the just- 

 mentioned line of fusion, extending from the 

 tubular branch on to axis of sponge. From a 

 photograph; \. 



10. Farrea mexicana. Gastral anchorate clavula ; x 450. 



11. " " " " " ; from above ; X 450. 



12. Eurete erectum tubuliferum. From a photograph. Upper end of sponge, from 



above ; \. 



