Plate IX. 



Fi(/. 1. Ascid'ia sordida, attached to the upper end of the tube of Pecti- 

 naria belgita. Veiy slightly enlarged. 



Fn/. 2. The same, from the other side. 



Fif/. ?>. Ptvascidia Flemingii, Alder, attached to a rootlet of tangle. 



Fir/. 4. Egg-ease of Nassa incrassata, Strom. Enlarged. 



Fif). 5. Tentacles of Ciicumaria lactea. Enlarged. The oral orifice 

 occupies the centre. 



Figs. & 7. Views of the oral region and tentacles of Si/napta inhcerena 

 in different degrees of contraction. 



Fig. 8. Anchor and plate of the foregoing. X 280 diameters. 



Fig. 9. Section of the shell of Cancer pagurus, showing the internal 

 processes of the hairs, The preparation was mounted by the 

 late Dr. Eraser Thomson. 



Fig. 10. Young of common Mussel attached by its byssus to the carapace 

 of a Shore-Crab. 



Fig. 11. Yoimg Mussels in the eye-cavities of the same crustacean, 

 causing the peduncles to project, and partially blinding the 

 Crab. 



Fig. 12. Defect of the carapace in the Shore-Crab, exposing the branchial 

 chamber exterior to the first pair of foot-jaws. 



Fig. 13. Abdomen and part of the cephalothorax of a female Shore- 

 Crab, with a parasitic Sacciilina carciiii and other abnormalities. 



Fig. 14. Sacculina parasitic on a male Portimus hohatiis. 



Fig. 1 o. Another view of the same, with the tail reflected. 



