56 
TOIBE I.— ASTR^ACEA. 
reticulately subseriate, but generally scattered ; surface reticulate with ridges 
which are triangular and nearly acute ; fossae short, 1 to 3 lines broad, and the 
larger often reticulate at bottom. Corallum below very finely striate. 
Barbadoes, West Indies. 
III. Foliaceous, bi/acial, 
10. A. Mycedia agaricites. — Bifacial and erect, fronds often aggregated, 
stout, semicircular in outline ; polyps transversely seriate ; ridges transverse, 
subacute, often flexuous, fossae 1^- lines broad and 1 deep. Corallum firm and 
compact. 
West Indies. 
11. A. Mycedia cristata [Lamarck ). — Bifacial and erect; fronds long 
and deeply lobed, lobes rounded, cristate ; polyps subseriate and often scat- 
tered ; ridges sometimes transverse, but generally sinuous and reticulate, sub- 
acute or obtuse, and including cells 2 to 2^ lines broad. 
West Indies. 
Genus IX.— PSAMMOCOEA.— Dana. 
AttacHed Fungidse, glomerate or ramose ; tentacles of polyps 
obsolete, polyps not seriate ; interstices sometimes flat, nsually 
tbroughout turgidly elevated, the surface, then, consisting of ex- 
cavate cells. Coralla porous; oririmes minute; lamellae very 
minute, often indistinct, and very minutely arenoso- denticulate, 
often irregular, not alternately smaller. 
I. Cespitose. 
1. PsAMMocoRA OBTUSANGDLA [Lamarck,) Dana.~ln subhemispherical 
tufts, very closely branched; branches flexuoso-plicate, many-lobed, lobes 
short and obtuse. Corallum with the oririmes distinct, circular, of a line 
broad, stars sometimes a little depressed, no where seriate. 
Indian Ocean ? — Lamarck. 
2. PsAMMOCORA PLicATA [Dana). — Cespitose, plano-convex, crowdedly 
ramose, branches J to f of an inch broad, flexuous and flexuoso-plicate, often 
coalescing below, obtuse ; polyps umber-colored, tentacles obsolete, greenish- 
white. Corallum with very minute oririmes, scarcely visible, often arranged 
in longitudinal series ; stars hardly distinguishable, not at all depressed. 
Plate 25, fig. 2, corallum, natural size ; 2 a, animals enlarged ; 2 6, surface 
enlarged. — Feejee Islands. — Exp. Exp. 
