TRIBE I. ASTRJSACEA. 347 



II. Psammocorcs glomemtce. 



3. PSAMMOCORA FOSSATA. (Dana.) 



P. subcylindrica, 5" crassa, superjicie fere plana, apice plano-rotundatd ; 

 super fide cellis scepe 1" elongatis, submeandrinis et hexastomatis, aliis 

 simplicibus, l'" pwfundis et 1J-2'" latis, excavatd ; collibus rotun- 

 datis. 



Subcylindrical, 5 inches thick, surface nearly even, piano-rotund at 

 top ; surface with cells often an inch long and meandering, and 

 containing 6 polyp-mouths, others simple, Ij lines deep, and l to 

 2 lines broad ; ridges rounded. 



Plate 26, fig. 2, outline view of corallum ; 2 a, surface of the same, 

 natural size. 



Feejee Islands. Exp. Exp. 



The only specimen of this species seen is five inches high, and the 

 same in its longest diameter. It has some resemblance to the columna, 

 but is not flat-topped, the cells are larger and deeper, and many elon- 

 gate and lobed, or meandering. 



The Astrcea Meandrina of Ehrenberg, from the Red Sea (op. cit. Gen. Ix. sp. 14.), 

 has many of the characters of the above species, and is thus described : " Subpedalis (et 

 orgyalis?), globosa, stellis contiguis, incequalibus, angustissimis, interdum polHcaribus, 

 angulosis, polystomis, lamellis subtilissimis, confertissimis, denticulatis et arenoso-asperis, 

 rotundatis, in crista non confluentibus ; animal fuscum, tentaculis nullis." It is supposed 

 by Ehrenberg, to be near the Astreea diffluens of Lamarck, which has entire lamellae, and 

 is incrusting and plano-undate. 



4. PSAMMOCORA COLUMNA. (Dana.} 



P. erecta ; crassima, subdivisa, lobis erectis, etfere contiguis, compresso- 

 cylindricis, apice truncatis, 1-3" latis; super fide, plana, cellis pro- 

 fundis, subangulatis, interdum lobatis, 1'" latis, raro 3'" elongatis 

 excavatd ; collibus rotundatis. 



Erect, very stout, subdivided above, lobes erect and crowded, com- 

 pressed-cylindrical, truncate at apex, 1 to 3 inches broad, surface 



