238 ZOOPHYTES. 



Subglobose. Corallum with the cells angular, often oblong and sub- 

 flexuous, deep, radiate from the centre ; ridges nearly naked, smooth 

 at apex. 



Plate 12, figure 9 a, section of cells and ridges, with the lamellae, 

 natural size ; 9 b, size and form of cells ; 9 c, transverse section of 

 corallum. 



West Indies? 



Lamarck, from whom this description is taken, farther remarks that 

 the lamellae are prominent only towards the bottom of the cell, the 

 upper part of the ridges, as well as the top, being nearly bare. It 

 approaches the favosa, but differs in the character just stated, and in 

 its smaller stars. 



To this species appears to belong the West India specimen figured 

 on plate 12 (figure 9, a, b, c.) It is a firm and rather heavy species; 

 the cells are angular, about a quarter of an inch broad, though often 

 oblong, and half an inch long, with the depth scarcely two-thirds the 

 breadth ; the lamellae are nearly even, very finely denticulate, and are 

 barely distinguished over the top of the ridge with a magnifying 

 glass : they are not appendiculate at base. In a transverse section 

 the septa are half a line thick, and quite solid ; the stars angular, 

 sometimes lobed, with the cellules not decompound. The specimen 

 has some resemblance to the rigida, but the lamellae are more even, 

 closer, and not dentate. 



Astrcea reticularis, Lamk., ii. 414, No. 21. Linn. Amren. Acad. i. tab. 4, fig. 16, 

 Lamarck refers to the fossil, Mad. favosa, which is beyond doubt a distinct species. 



41. ASTR^EA PETROSA. (Dana.) 



A. convexa. Corallum subcellulosum, robutum : transverse secto, stellis 

 interdum orbiculatis sed scepius oblongis lJ-2"' latis, et l-5"' 

 longis, multiradiatis, radiis bene tenuibus, cettulis simplicibus ; septis 

 1'" crassis et persolidis. 



Convex. Corallum subcellular, firm : in a transverse section, the 

 stars orbiculate, commonly oblong, 1J to 3 lines broad, and 1 to 5 



