42 
TRIBE I. — -ASTR^ACEA. 
8. Merulina rigida (Dana).— Very much ramose, branches proliferous j 
and sometimes coalescent, 3 to 6 lines thick, covered with small contiguous 
cones ; branchlets attenuate, often curved ; animals like those of the Monticu- j 
laricd, Corallum with small lamello-radiate cones, which are unequal and 
scarcely compressed at apex of branchlets, lax and attenuated ; lamellae gran- 
ulous. 
Plate 17, fig. 1, corallum, natural size ; 1 a, one of the conelets, enlarged ; 
1 bj animals, enlarged ; 1 c, part of a transverse section of stem, enlarged.— 
Feejee Islands. — Exp» Exp. 
Genus XII.— ECHINOPOEA.— Lamarck. 
Explanate or cumulato -ramose ; polyps a little prominent^ 
placed perpendicularly with the surface of the zoophyte ; the 
margin and not the disks widening by growth in budding (as 
in the Orhicellce). Coralla striate and echinulat^, nearly solid; 
calicles convex, echinulate. 
1. Echinopora undulata (Dana). — Foliaceous, erect, bifacial, undulate. 
Corallum very thin, on each surface fine striate and spinuloso-asperate, with 
scattered cells scarcely tumid, 6 to 8 rayed. 
Plate 17, fig. 3, corallum, natural size ; 3 a, cell of the same. — Sooloo Sea, 
East Indies. — Exp. Exp. 
2. Echinopora rosularia {Lamarck). — Explanato-foliaceous, suborbicu- 
late, unifacial. Corallum above striato-asperate, calicles echinate, below striate. 
New Holland Seas. — Peron and Lesueur. 
3. Echinopora ringens {Lamarck,) Blainville. — Subturbinate, lobed. Co- 
rallum with irregular cells, subconfluent, sinuous, contiguous ; margin thick, 
convex. 
West Indies ? — Lamarck. 
4. Echinopora reflexa {Dana). — Foliaceous, unifacial; folia suberect, 
sides reflexed and often coalescing by the margin (thus forming tubes) ; color, 
umber; mouth quite small; tentacles none, except the minute tubercles over 
the spines. Corallum above finely spinuloso-striate ; calicles spinulous, tumid, 
rather more than ^ of an inch broad ; large lamellse 10 to 15, denticulate ; 
outer surface, near the margin only, obsoletely fine striate. 
Plate 17, fig. 2, corallum, natural size ; 2 a, animal enlarged ; 2 b, transverse 
section of a folium, enlarged. — Feejee Islands. — Exp. Exp. 
5. Echinopora aspera {Ellis,) Dana. — Explanate, partly incrusting, mar- 
gin thin and undulate ; sometimes gibbous above and cumulato-subramose ; 
