6. Fissurella entire, covered with its "shell, which is set in the edges of its 



mantle. 



g. The heart. 



7. . . open. 



a. The disk of the foot. 

 bb. .. circular muscle which 



joins it to the shell, 

 and which has been 

 cut. 



b. A portion of this muscle re- 



maining with the man- 

 tle. 



cc. The mantle thrown back, and 

 seen on the under side. 

 d. .. hole with which it is 



pierced. 

 ee. .. branchiae. 

 f. .. anus. 



8. Vermeius, Adanson. 



c. The tentacula. 

 Y. .. eyes, 

 P. .. foot. 

 F. Cylindrical filaments. 



9. The same animal seen underneath. 



p. The foot put on one side, to make it more apparent. 

 B. The mouth. 



hh. 

 ii. 

 k. 

 I. 



mm. 

 nn. 

 o. 

 pp. 



7- 



auricles, 

 intestine, 

 oesophagus, 

 pharynx, 

 salivary glands, 

 lateral ganglions of the brain . 

 extremity of the tongue, 

 liver, 

 ovarium . 



o. Operculum. 

 M. Mantle. 



A. Aperture by which the animal 

 breathes. 



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