PLATE XIV. 



IsoDiOTTA DEFOEMis, Bowerbank. 



Fig. 1. — Mr. Peach's type-specimea on tlie inside of 

 a valve of Mytilus edulis. From Wick. 



Fig. 2. — A portion of tlie dermal membrane. 



Fig. 3. — An incipiently spined acuate spicule of the 

 skeleton. 



Fig. 4. — One of the very minute, simple, bihamate, 

 retentive spicula. 



Fig. 6. — One of the equally minute, bidentate-equi- 

 anchorate, retentive spicula. 



IsoDiCTYA COLLINA, Bowerlank. 



Fig. 6. — The type-specimen attached to a root of 

 Laminaria. In the Rev. A. M. Norman's cabinet. 



Figs. 7 and 8. — Two other specimens from the 

 same locality. 



Fig. 9. — The subfusiformi-acuate spicule of the 

 skeleton. 



Fig. 10. — One of the long and slender acuate 

 tension spicules. 



Fig. 11. — The large and slender, contort, bihamate, 

 retentive spicule. 



Fig. 12. — A bidentate equi-anchorate spicule. 



Fig. 13. — A dentate palmato-equi-anchorate spicu- 

 lum. 



