TRIBE III. MADREPORACEA. 
S3 
naked, stout pedicellate ; above, branchlets crowded, digitiform, nearly simple, 
rarely proliferous, subterete, 2 to 2^ inches long and 4 to 5 lines thick, sub- 
acute, branchlets of the margin horizontal and elongate. Corallum with the 
lateral calicles very prominent, compressed nariform, very finely striate ; star 
often distinct, two of the lamellae a little the broadest. 
Plate 34, fig. 2, corallum, natural size; 2a, branchlet, ditto; 2&, profile of 
calicles. — Tahiti, Society Islands. — E^p. Exp. 
20. Madrepora digitifera [Dana). — Broad, nearly flat above, base of 
the frond solid and disk-form ; above, branchlets crowded, digitiform, scarcely 
terete, and subacute, 2i to 3 inches long and 4 to 5 lines thick, often short 
proliferous. Corallum with the apical calicle a little prominent, scarcely a 
line broad ; the lateral crowded, divaricate, dimidiate, erect, and not at all 
compressed, f of a line long, lip rather thick, with some scattered immersed 
cells ; star short 6-rayed, exterior lamella quite prominent. 
21. Madrepora globiceps [Dana). — Broad cespitose, convex above, with 
a solid disk-form base; above, branchlets erect digitiform, crowded, subangu- 
lar, 2^- inches long and i to f of an inch thick, rounded at apex. Corallum 
having the apical calicle scarcely at all prominent, a line broad ; the lateral 
crowded, short, tubiform or tubo-nariform, obsoletely striate, oblique at apex, 
aperture elliptical, star distinct. 
Plate 34, fig. 3, branchlet, natural size.— -Tahiti, Society Islands.— Exp, 
22. Madrepora effusa [Dana). — -Broad cespitose, convex above, base 
nearly solid and disk-form ; above, branchlets crowded, digitiform, inches 
long, and 4 to 5 lines thick ; at the margin, the branchlets scarcely free. Co- 
rallum having the apical calicle stout, cylindrical, rather more than a line 
broad, the lateral much crowded and unequal, compressed-nariform lines 
long, sometimes tubo-nariform and proliferous : under surface crowdedly cov- 
ered with short calicles. 
Ceylon, Indian Ocean. — Rev. G. A. Apthorp. 
23. Madrepora corymbosa [Lamarck). — Broad cespitose, convex above; 
branchlets digitiform, subsimple, 3 to 4 lines broad and 24 to 3 inches long, 
subterete. Corallum with the apical calicle large (1 to IJ lines broad); the 
lateral I 4 to If lines long, tubiform, with the summit oblique and margin 
echinulate ; exterior striate and scabrous ; a few minute calicles interspersed ; 
star very short or indistinct ; two of the lamellce a little the most prominent. 
East Indies, and Indian Ocean. 
24. Madrepora appressa [Ehrenherg). — Prostrate, the horizontal branches 
coalescing into a plate which is nearly entire, flattened and naked below ; 
above, branchlets erect, crowded, spiciform, nearly terete, 24 to 3 inches long 
and 3 lines thick. Corallum with the apical calicles a little prominent; the 
