82 



access to the vacuum, and the animal be immediately 

 loosened. But whilst fixed by its inferior surface, the mus- 

 cular fibres of the upper convex surface would, by their 

 contraction, draw down the whole upper surface, and at the 

 same time widen the central longitudinal opening, and ne- 

 cessarily expel the contents of the ventricular cavity. The 

 immediate subsequent relaxation of these fibres would then 

 occasion the refilling of the cavity ; and thus the alternate 

 filling and emptying of the ventricular cavity would be 

 continued. The examination of the figure given by Guettard, 

 Memoires, Table xxi. fig. 17, 18, confirms this opinion. 



The figure given by Scheuchzer, Herb. Diluv. Tab. xiii. 

 fig. 1, appears to be a correct representation of the second 

 species, C. hemisphcerica. 



Fungia. A stony, free polypifer, simple, orbicular or 

 oblong ; convex and lamellated in the upper part, with an 

 oblong central groove ; concave and rough beneath. The 

 star single, lamellated, and subproliferous, occupies the 

 upper part ; the lamellae are dentated or rough on the side. 



The extensive surface which almost every species of this 

 genus possesses, formed by a single star, probably the labour 

 of a single animal, shows the propriety of placing it in a 

 distinct genus. 



1. F. semilunata Compressed at the sides, striated outwardly ; 



the edge bowed ; a longitudinal groove, and a short pedicle. 

 Fossil. 



2. compressa Indian Seas. 



3. cyclolites Indian Seas. 



4. patellaris. . . . Sol. and Ellis, Tab. xxviii. fig. 1 4. 



5. agariciformis. . . . Sol. and Ellis, Tab. xxviii. fig. 5, 6. 



6. scutaria. . . . Rumph. Amb. vi. Tab. Ixxxviii. fig. 4. 



7. limacina. . . . M. pileus. Sol. and Ellis, Tab. xlv. 



8. talpa Seba, iii. Tab. iii. fig. vi. and Tab. cxii. fig. 3. 



9. pileus. . . . Rumph. Amb. vi. Tab. Ixxxviii. fig. 3. 



Fossils of this genus have been found at Steeple Aston. 



