162 



Proceedings of the Royal Irish Academy. 



Fig. 

 7. 



8. 



o. 



9. 



14. 

 10. 



Cymbadis gossei 



Aetii 



11. 

 12. 

 13. 

 15. 

 16. 



Actinostola atrostoraa. Detail of a small portion of the radial-muscle band 

 of the oral disc. Obj. LJ-. 

 Part of a T. S. of the oral disc. Obj. H. (Note 

 that this is on same scale, approximately, as 

 fig. 7, but represents a different part of the 

 disc.) 

 „ Exact detail of a portion of the whole width of the 



lower end of the sphincter. Oc. 3. Obj. § . 

 Transverse section of a tentacle. Low magnification. 

 Detail of a small piece of the lower part of the 



sphincter. Oc. 3. Obj. f. 

 Part of a fairly large mesentery. Obj. 1$. 

 Detail of part of the whole width of the sphincter at 

 its best-developed but not quite its widest; point. 

 Oc. 3. Obj. §. ( The dots here are simply shading, 

 and do not represent muscle fibres in section ; 

 some of the larger ones are pigment granules.) 

 of fig. 10, more enlarged. Oc. 3. Obj. \. 

 - nailer dots merely shading, as before.) 

 A whole imperfect mesenteiy of moderate size, to 



show general proportions. Obj. \\. 

 Parietal muscle of a small imperfect mesentery. 

 Oc. 3. Obj. Vj. 



w processes of the mesogloea of a mesentery, 

 i Not from the pennon itself.) Oc. 3. Obj. J. 

 Part of the whole thickness of a mesentery in the 



middle of the pennon. Oc. 3. Obj. $. 

 Part of T. S. of a tentacle, to show longitudinal 

 musculature. Oc. 3. Obj. §. 



Plate XVIII. 



1. AeUnenuu . A few processes from a mesenterial pennon. Oc. 3. 



Obj. £. 



2. Actinermu . Detail of portion of lower part of sphincter. Oc. 3. 



Obj. |. 



3. „ Part of pennon of a medium-sized mesenteiy. Oc. 3. 



Obj 



