SIGARETUS. 257 



Besides these two sets of valves, there is generally a shelly plate, 

 serving as a sort of foundation to the rest. The Sessile Cirripedes 

 may be thus arranged. 



1. Tubicinella. Six parietal valves, tube-shaped, opercular 



valves perpendicular. Fig. 14. 



2. Coronula. Six parietal valves, opercular valves horizontal. 



Fig. 15, 16, 17, 18. 

 These two genera fix themselves in the skin of the Whale. 

 The latter has been divided into the genera Chelonobia, 

 Cetopirus, Diadema, and Chthalamus. 



3. Platylepas. Valves divided, each having a prominent 



internal plate. Fig. 19. 



4. Clitia. Parietal valves four, opercular valves two, valves 



dove-tailed into each other. Fig. 20. 



5. Eemineus. Parietal valves four, opercular valves four. 



Fig. 22. 



6. Conia. Parietal valves four, thick and porous at the base. 



Fig. 21. 



7. Octomeris. Parietal valves eight. Fig. 24. 



8. Catophragmus. Parietal valves numerous, irregular. 



Fig. 23. 



9. Balanus. Parietal valves six ; opercular valves four, placed 



against each other conically in pairs. This genus has 

 been divided into Acasta, Conoplea, Chirona, and Balanus. 

 Fig. 25, 26, 27. 



10. Creusia. Parietal valves four, supported on the edge of a 



funnel-shaped cavity. Fig. 28. 



11. Pyrgoma. Paries simple, supported on a cavity. This 



genus has been divided into the genera Nobia, Savignium, 

 Pyrgoma, Adna, Megatrema, andDaracia. Fig. 29 to 33. 



SETIFEROUS. Hairy. 



SHANK SHELL. The vulgar name for the shell designated Murex 

 Rapa. It is used in Ceylon for ornamental purposes. 



SIDEROLITES. Montf. A genus of microscopic Foraminifera. 



SIGARETUS. Lam. Fam. Macrostomata, Lam.— Descr. Sub- 



