TRIBE III. MADREPORACEA. 
49. Madrepora hystrix {Dana), — Low fruticose, spreading ramose, pro« 
liferous, branches and polyps very divaricate and sometimes reflexed. Coral- 
Iiim with the apical calicle oblong, a line broad ; the lateral unequal (l^- to 4 
lines long), divaricate, scattered, tubiform or tubo-nariform, some obsolescent, 
some proliferous, very finely scabro-striate, stout, but margin not thick. 
Plate 40, fig. 1, corallum, natural size; plate 31, figs. 5, 5a, view of calicle 
and cell, enlarged. — Feejee Islands. 
50. Madrepora divaricata (i)ana).— Shrubby arborescent, much and 
spreading ramose, a little proliferous; branches divaricate, arcuate, subterete, 
f of an inch thick ; branchlets attenuate, 4 to G lines thick. Corallum smooth ; 
apical calicle large (14 lines broad), exsert; the lateral remote, divaricate, 
very stout, scarcely striate, some long-tubifonn (2 lines long), a few larger 
and proliferous, many short and round-nariform ; star sometimes distinct, with 
two of the lamellae most prominent. 
Plate 41, fig. 2, part of corallum, natural size; 2a, extremity of branch.— 
Feejee Islands. — Exp. Exp, 
51. Madrepora abrotanoides (Lamarck). — Fruticose, spreading ramose, 
branches scarcely terete, ^ to ^ o? an inch thick, summit branchlets 3 to 4 
lines thick, arcuate and pyrarnidato-attenuate, very proliferous, with short and 
unequal incipient branchlets. Corallum nearly smooth ; apical calicle a line 
broad, exsert; the lateral, crowded, compressed, tubiform or tubo-nariform, 
with the margin stout, very unequal, many proliferous, many obsolescent; 
others 2 lines long and four-fifths of aline thick, scarcely striate ; aperture 
oblong, star distinct, two of the lamellae most prominent. 
Plate 41, fig. 1, part of corallum, natural size; la, extremity of branch.— 
Feejee Islands.^ — Exp. Exp. 
52. Madrepora austera (Dana). — Fruticose, spreading ramose, and 
very proliferous, branches nearly terete, and tapering above, with numerous 
unecjual lateral branchlets and proliferous polyps. Corallum scabrous; apical 
calicle stout (1 to lines broad), exsert ; the lateral ascending, rather crowded, 
tubiform and tubo-nariform, 1 to 2^ lines long, rough and striate ; aperture 
circular, star distinct but deep, six-rayed, wfith two of the rays most prominent. 
53. Madrepora cervicornis (Lamarck).. Arborescent, very large, 
spreading and remotely ramose, below, to 2 inches thick, branchlets very 
long, h. to f of an inch thick, arcuate, terete, gradually attenuate. Corallum 
scabrous, apical calicle stout (14 lines), and elongate; the lateral subequal, 
round-nariform, scarcely compressed, 14 to 2 lines long, and nearly a line in 
diameter, strongly striate, margin not thick, star distinct, 
West Indies. 
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