Plate IX. 
Fig. 1. Ascidia sordidci, attached to the upper end of the tube of Pecti- 
naria belyica. Very slightly enlarged. 
Fig. 2. The same, from the other side. 
Fig. 3. Paraseidia Flemingii, Alder, attached to a rootlet of tangle. 
Fig. 4. Egg-case of Nassa incrassata, Strom. Enlarged. 
Fig. 5. Tentacles of Cucumaria lactea. Enlarged. The oral orifice 
occupies the centre. 
Figs. B & 7. Views of the oral region and tentacles of Synapta inhcerens 
iu 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. Fraser Thomson. 
Fig. 10. Young of common Mussel attached by its byssus to the carapace 
of a Sliore-Crah. 
Fig. 11. Young Mussels iu 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 ceplialothorax of a female Shore- 
Crab, with a parasitic Saccidina carcini and other abnormalities. 
Fig. 14. Saccidina parasitic on a male Portunus liolsatus. 
Fig. 15. Another view of the same, with the tail reflected. 
