76 (JRlilCKLLA 



ASTEiEACE^ M.-Edw. & H. 

 OKBICELLA Dana. 



IMlastnca M.-Edw. & II. Hist. Nat. Jes Corall. 



Aslncit M.-Edw. & II. Compt. ivnd. ile I'Acad. ilc-i .Sc. 1848, ami Ann. iles Sc. Xat., ?.' .Sci-., t. XI. 



The name adojjted by Dana covers so nearly the same groimd as 

 the generic division called Heliastrasa by Milne-Edwards and Haime, 

 that it is retained here, as had already l)een done ))y Mr. Verrill in the 

 Bull. Mus. Comp. ZooL, No. o. 



Orbicella cavernosa Vr.i;un,i,. 



Marlrcpora radlala ? Ellks. {Aslnm, Ileliaslrmi, OrUceUa nuHiila Am-t.) 



Mudrcimra carcninsa Esper, Pflaiiz. Sujjpl., p 18, PI. 37.* 



Aslrx'a ar(/iis Lamk. 



Tuhashra cavernosa Blainv. 



Orbicella arffus Dan.\. 



Aslrea cavernosa M.-Enw. & H. Ann. des Sc. Nat., S' Ser., t. XI. 



Ilclia.ilnea cafcniosn M.-Enw. & II. Hist. Nat. des Corall. 



lleliaslnta conjerta? M.-Ei>w. ^-^ II. 



There is considerable variation among the specimens from Florida in 

 the Mus. Comp. Zool., enough apparently to warrant placing them 

 among the three species named in the .-synonymy; but by carefidly 

 examining the diilercnt pai'ts of each s])(>cimen, passages from one to 

 the other can l)e found. Tims young polypidoms, expanding ra])idly 

 laterally, and with ratlier distant poly])s. appear at first to dilfcr con- 

 siderably from strongly con\ex ones with crowded caliclcs ; the cost:v 

 are longer, flatter, and less sluirply denticulate, and the border of the 

 calicles le.ss elevated. 



The size of the calicles, relied on to divide tiie genus into groups, by 

 Milne-Edwards and Haime, is a very uncertain character ; one specimen 

 has in one part liie calicles varying from 3.5 to -1.0 mm., in another ])art 

 from 7 to 8 mm. The same specimen luis in some parts the contiguous 

 walls united solidly, with very few or no exotlieeal cells, in others sep- 

 arated by an abundant cellular exotheca. In worn specimens the last 

 cycle disappears first, for that reason j)robably Orbicella (Aftuhrjiora) 

 ;7«&</«' Ellis has been characterized by Milne-Edwards and llaime as 

 having but three cycles. 



This coral is generally found from 2 to IT) fiithoms deep, fonning 

 sometimes masses of considerable size. It is al.'^o occasionally found in 

 smaller masses in le.-<ser depths on the leef 



• I liavo not seen tliis figiiie, llir ccii; of l^jicr wlj'uli 1 have cuiisidfed bi-iiig incimipUtf. 



