164 Proceedings of the Royal Irish Academy. 



Fig. 



2. Uhondrodactis duplicate. T. S. of a tentacle. Obj. 1\. 



3. „ „ Sketch of sphincter, as seen with a lens. 



4. „ „ Part of T. S. of Oral disc. Obj. H. 



5. „ „ Part of a primary mesentery, showing the 



pennon. Obj. 1^. 



6. „ ,. Parietal muscle of a fourth-cycle mesentery. 



Oc. 3. obj. 3. 



7. „ „ Whole primary mesentery, as seen with lens. 



8. „ „ A linger of mesogloea from a T. S. of a tentacle, 



showing longitudinal muscle-fringe and nerve- 

 layer, &c. Oc. 3. Obj. g. 



9. „ „ Process from pennon of third-cycle mesentery. 



Oc. 3. Obj. I 



Plate XX. 



1. Section (longitudinal) passing through the margin of the body and the 



base of a tentacle of the specimen of Bolocera tuediac figured in 

 PI. XIY, fig. 2. It shows the body sphincter, and both sides of the 

 tentacle sphincter. Obj. 1$. 



2. Carlgrtniadi Part of T. S. of tentacle. Oc. 3. Obj. §. 



8. „ : I '. S. of oral disc. Oc. 3. Obj. 5. 



9. „ „ Diagram showing the arrangement of the macro- 



mesenteries and the primary micro mesenteries 

 in one-half of the animal. 



3. Bolocera tuediac. Part of a T. S. of a tentacle of the specimen figured in 



PL XIV, fig. 2. Obj. 1|. 



4. „ Muscular portion of a mesentery of the last cycle but 



one, of the specimen figured in PI. XIV, fig. 2. 

 Obj. 11. 



5. „ „ Sphincter of a different specimen from that figured in 



PI. XIV, fig. 2. Obj. 1J. 



6. „ „ Sphincter of a specimen from the North Sea (not in 



the present collection). Obj. li. 

 7 Bolocera hmgicornis, Carlgren. Sphincter. Obj. li. 



