84 



Meandrina. — A stony polypifer, fixed, in a simple he- 

 misphserical or sphaeroidal mass. 



On the convex surface are excavated, open, winding, 

 ambulacrae, lamellated on each side. The lamellae are trans- 

 verse and parallel, adhering on each side of hillock-shaped 

 ridges. 



The lamellae abut upon the hillock-like ridges ; and the 

 ambulacra may be compared to tortuous vallies, separated 

 by corresponding hills : the lamellated ridges occupy the 

 interstices of the tortuous vallies which held the polypes, 

 and thus separated them. 



1. Meand. lahyrinthica. . . . Mad. labj^inthica, Sol. and Ellis, Tab. 



xlvi. fig. 3, 4. 



2. M. cerehriformis. . . . Shaw's Miscel. iv. Tab. cxviii. The Ame- 



rican Seas. Seba Mus. iii. Tab. cxii. fig. 5, 6. 



3. — dcedalea. . . . Mad. dsedalea. Sol. and Ellis, Tab. xlvi. fig. 1. 



4. — pectinata. . . . Lin. Sol. and Ellis, Tab. Ixviii. fig. 1. 



5. — areolata. . . . Sol. and Ellis, Tab. xlvii. fig. 4, 5. 



6. — crispa. . . . Seb. Mus. iii. Tab. cviii. fig. 3 — 5. 



7. — gyrosa Mad. Sol. and ElUs, Tab. li. fig. 2. 



8. — phrygia. . . . Mad. Sol. and Ellis, Tab. xlviii. fig. 2. 



9. — filograna. . . . Mad. filograna, Gmelin. 



None of these species are mentioned as having been 

 found fossil ; they are however found in this state : some 

 fine specimens are in the British Museum. Very beautiful 

 specimens, impregnated with quartz, are in the collection 

 presented by Dr. Nugent to the Geological Society, col- 

 lected by him on the Island of Antigua, with several other 

 silicious remains of astrecE, madreporce, &c. 



Hydnophora. — A stony polypifer, fixed and incrusting 

 other bodies ; either forming a subglobose, gibbous, or lo- 

 bated mass, or spread in subfoliaceous lobes ; the upper 

 surface set with little stars raised in pyramids or little 

 mounts. 



