24 



Plate III. 



Fig. 1. Thi/one vcrcoi. n. sp. 



a,b,c,d — Various ossicles from perisome, x 200. 



e,/,f/ — Ossicles from pharyngeal processes and from 

 tentacles, x 200. 

 ,, 2. Cucumuria striata, n. sp. 



a,h,c,d — Ossicl'es from perisome, x 275. 

 ,, 3. Thyone nigra, n. sp. 



a,b,c — -Ossicles from perisome, x 250. 



d,e — Ossicles from tube feet, x 250. 

 ,, 4. Thyone nigra, calcareous ring. Enlarged. 

 ,, 5. Phyllophorus ventripes, calcareous ring. Enlarged. 



Plate IV. 



Thyone vercoi. Diagram of a section of the pharyngeal wall and 

 of a single process dependent therefrom. 



a — Spicules as in plate iii., fig. i., e,f,g. 



b — Endothelium. 



c — Ljniiphocytes. 



d — Longitudinal muscle. 



e — Connective tissue. 



/ — Circular muscle. 



g — Peritoneum . 



