TRIBE I. ASTR^EACEA. 339 



scarcely visible without a glass, appear slightly to diverge, so as to 

 meet successively in the depressions. The specimen affording this 

 description, belongs to the Lyceum of Natural History at Utica, New 

 York. It is ten inches broad, with a thickness of about an eighth of 

 an inch, and a thin margin. 



SUBGENUS II. MYCEDIA. 



AgaricicE transversim aut reticulate cotticulatce, fossis interdum regulari- 

 bus, sed scepius cellis distinctis compositis. Corolla robusta, vix minimi 

 cellulosa. 



Surface with transverse or reticulate ridges; fossae sometimes long 

 and even, but usually consisting of separate excavate cells, clustered 

 or seriate (cells sometimes distinct only along the fossae near the 

 margin). Coralla very compact. 



I. Mycedia unifrontes. 



6. A. MYCEDIA CUCULLATA. (Ellis.) Oken. 



A. unifrons, stipitata, subturbinata ; frondibus sape convolutis et bast 

 coalitis ; supra concava, transverse collicutata, collibus subflexuosis et 

 irregularibus, etiam multis cellis profundis sparsis. Corallum robus- 

 tum, subtus subtilissime striatum. 



Unifacial, stipitate, subturbinate ; fronds often convoluted and coa- 

 lescing at base; above concave, with transverse ridges subflexuous 

 and irregular, and frequent deep cells interspersed. Corallum very 

 firm and compact, below very finely striate. 



West Indies. 



When young this coral forms a simple funnel-shaped frond sup- 

 ported below at centre ; but when larger it consists of several involved 

 fronds spreading from the same base, or cucullate in arrangement. 



