PLATE XIV. 



ISODIGTYA DEFORMIS, Bowerbank. 



Fig. 1. Mr. Peach's type-specimen on the inside of 

 a valve of Mytilus ed:dis. From Wick. 



Fig. 2. A portion of the dermal membrane. 



Fig. 3. An incipient ly spined acuate spicule of the 

 skeleton. 



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

 retentive spicula. 



Fig. 5. One of the equally minute, bidentate-equi- 

 anchorate, retentive spicula. 



ISODICTTA COLLINA, Bowerbank. 



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

 Lominaria. 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. 



