274 SESSILE CIEEIPEDES. 



7. Leptoconchus, outer lip reflected. Fig. 11. 



8. Stylieer, spiral, thin, globular, living in Starfish. Pig. 



12, 13. 

 The three last genera should certainly find some other place 

 in the system. 



SERPULOEBIS. Sassi, 1827. 



SESSILE CIEEIPEDES. Lam. (Sessilis, low, dwarfish.) An 

 order of Cirripedes, consisting of those which are attached by 

 the base of the shells, containing the genera Tubicinella, Balanus, 

 Coronula, Acasta, Pyrgoma, Creusia. To which may be added 

 some other genera enumerated in explanation of figures 14 to 33. 

 The shells of the Sessile Cirripedes consist of two difierent sets 

 of valves : 1st. The parietal ys^Yos, or pieces arranged in a circle, 

 side by side, around the body of the animal, (an arrangement 

 designated coronular by DeBlainville.) 2nd. The opercular valves, 

 or pieces placed so as to enclose the aperture. Between those 

 opercular valves the cilise protrude which characterize the class. 

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

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

 pedes may be thus arranged. 



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



valves perpendicular, Eig. 14. 



2. CoEONTJLA. Six parietal valves, opercular valves hori- 



zontal. Eig. 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. Plattlepas. Valves divided, each having a prominent 



internal plate. Eig. 19. 



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



dove-tailed into each other. Eig. 20. 



5. Elmineus. Parietal valves four, opercular valves four. 



Eig. 22. , 



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



Eig. 21. 



7. Octomeris. Parietal valves eight. Eig. 24. 



