TRIBE I. ASTR^ACEA. 239 



lines long, many-rayed, rays very thin, with the cellules simple ; 

 septa a line thick and quite solid. 



Plate 12, fig. 12 a, transverse section of corallum, natural size ; 12 b, 

 vertical section of same. 



The very compact septa, and the neat thin rays and rather small 

 star, readily distinguish this species from the others described. 

 Besides, the cellules below the star, in a vertical section, are more than 

 half a line long. The nitida is similar in its solid septa, but the 

 cellules below the star are very minute. The ridges are sulcate. 



Mad. detrita, Esper, Pflanz. Fortsetz. i. Astrcea detrita, Blainv., Man. 367. 



26, tab. 41, a figure of a worn specimen, An apology can hardly be required for 



from the China Seas, sent him by M. changing a specific name derived merely 



Chemnitz. from the fact that the specimen examined 



Astrcea detrita, Lamk., ii. 406, No. 6. was a worn one (detritum). 



42. ASTHMA PURPUREA. (Dana.} 



A. hemispherica ; polypis J" latis, discis late virentibus, tentaculis nume- 

 rosis, purpureis. Corallum subcellulosum, robustum ; cellis angu- 

 latis, subprofundis, 4-5'" latis, intus non coronatis ; collibus triangu- 

 latis, subtiliter sukatulis ; lamellis confertis, rzqualibus, subtilissime 

 denticulatis, apice fere integris et paululum prominulis : transverse 

 secto, stettis suborbiculatis, multiradiatis, cellulis simplicibus, angustis- 

 simis ; septis sottdis, cellulis paucis, minutissimis. 



Hemispherical; polyps half an inch broad, disks bright-green, tenta- 

 cles numerous, purple. Corallum subcellular, firm ; cells angular, 

 rather shallow ; 4 to 5 lines broad, not coronate within; ridges tri- 

 angular, very delicately sulcate ; lamellae crowded, even, very finely 

 denticulate, nearly entire, and but slightly prominent at apex ; in a 

 transverse section, stars nearly circular, many-rayed, cellules sim- 

 ple, very narrow ; septa solid, cellules rare and very minute. 



Plate 12, fig. 10, natural size; 10 a, cells, do.; 10 b, profile of cell 

 and lamelke, enlarged; 10 b', same, natural size; 10 c, vertical sec- 

 tion, enlarged; 10 d, same, natural size;. 10 e, transverse section, 

 enlarged four diameters, from a part of the corallum where the cells 

 were small. 



