TRIBE I. ASTR^EACEA. 255 



The short gyri and rather steep triangular lacerate ridges are strik- 

 ing characters of this species. The septa are not over half a line 

 thick, and the erose lamellse projecting above unequally, give the 

 ridges a ragged appearance. The bottom of the cell is convolute- 

 porous, but very narrow. Of the larger lamellse that reach the centre 

 of the cell, there are about ten to half an inch ; with the intermediate, 

 there are about sixteen in all, in this distance : the corallum is conse- 

 quently quite open cellular. 



This species grows in hemispheres, which are sometimes six inches 

 in diameter. 



Mad. dcedcdea, Ellis and Solander, 163, tab. Meandrina dfedalea, Lamk., ii. 387, No. 3. 



46, fig. 1 ; a good figure. , Lamour., Exp. Meth., 55, tab. 46, 



, Esper, Fortsetz. i. 63, tab. 57, figs. fig. 1 ; Encyc., 508. 



1 and 2. Figure 1 is from Ellis. , Blainville, Man., 357. 



2. MEANDRINA SPONGIOSA. (Dana.) 



M. globosa aut hemispherica, discis interdum simplidssimis, scepius linea- 

 ribus et subgyrosis; gyris 34'" latis, raro 2" longis. Corallum per- 

 ceUulosum, non robustum ; cottibus triangulatis ; fossis profundis ; 

 septis tenuibus et interdum inflatis ; lamellis subremotis, apice suba- 

 cutis, subcequalibus, tenuissimis, kviter eroso-denticulatis. 



Globose or hemispherical ; disks sometimes quite simple, but usually 

 linear and subgyrose ; gyri 3 to 4 lines broad, and rarely 2 inches 

 long. Corallum very light cellular ; ridges triangular ; fossae deep ; 

 septa thin, but also often inflated ; lamellae rather distant, subacute 

 at apex, subequal, very thin, delicately eroso-denticulate. 



Plate 14, figure 17 a, section of fossae and profile of lamellae. 

 West Indies? Bost. Nat. Hist. Soc. 



This species has the general habit of the dedaka, but the texture 

 is very cellular and more fragile, and the lamellae thinner, more 

 even, and less deeply denticulate. The cells are sometimes simple, 

 even over a considerable surface, but in general they are from half to 

 one inch in length, and sometimes two inches and a half. The bot- 

 tom of the fossae is very loosely convolute ; and the depth fully equals 

 the breadth at top or even exceeds it. While the septa are quite thin 



