TRIBE I. ASTR.EACEA. 259 



latis. Corallum cellulosum, robustum ; fossis fundo subcellulosis : 

 transverse secto, septis f '" crassis, lamettis subcrassis cequalibus. 



Hemispherical ; linear disks not long, gyrose ; gyri 2 to 3 lines broad. 

 Corallum cellular, firm; fossae at bottom subcellular: in a trans- 

 verse section, septa ^ of a line thick, lamelke rather stout, equal. 



Plate 1 4, figure 5 a, transverse section of corallum, natural size ; 5 b, 

 vertical section of same. 



Wakes Island, Pacific Ocean. Exp. Exp. 



In a beach specimen of this species, the only kind seen, the ridges 

 are worn down, as in the last. The section of the cell presents a 

 simple series of cellules alternating with stout lamellae, of which there 

 are about sixteen to half an inch. In a vertical section the surface is 

 coarsely striate, owing to the stoutness of the lamellae. This character 

 distinguishes it from the strigosa, which it approaches in the breadth 

 of its gyri : the septa are also thicker than in that species. It differs 

 from the labyrinthica in its narrower and much shorter gyri, thinner 

 septa, and the lamellae not quite as crowded. 



7. MEANDRINA VALIDA. (Dana.) 



M. subhemispherica ; gyris tortuosis et gyroso-lobatis, 3-4'" latis. Co- 

 rallum subcellulosum, robustum ; septis medio subcellulosis, subacutis, 

 fere triangulatis, 3'" altis et basi fa" crassis, lamellis tenuissimis. 



Subhemispherical ; gyri tortuous and tortuously lobed, 3 to 4 lines 

 broad. Corallum subcellular, firm ; septa somewhat cellular at 

 middle, subacute, nearly triangular, J of an inch high, and fa thick 

 at base ; lamellae quite thin. 



Plate 14, fig. 11 a, worn surface, natural size; 11 b, outline of fossa 

 and septa, do. 



Worn specimens of this species have the septa very prominent, 

 owing to their unusual thickness and texture, while at the same 

 time, the lamellae are very thin : the remains of the lamellae of the 

 ridges in some parts barely striate faintly the surfaces of the septa. 



