TRIBE III. MADREPORACEA. 
99 
Gtenus II. — SIDEROPOE A . — Bl ainville. 
Furcato-ramose ; cells with 6 lamellse meeting at centre in an 
axis, and forming a star of six rays. 
1. SiDEROPORA DiGiTATA {PallaSf) Blamvilk. — Branches i to ^ an inch 
thick, rarely f of an inch, obsoletely compressed, often a little tumid at inter- 
vals. 
Red Sea and East Indies. Sooloo Sea. — Exp, Exp. 
2. SiDEROPORA ELONGATA {Lamarck^) Blainville. — Branchlets elongate, 
cylindrical. Corallum with the cells sex-dentate; superior margin a little 
prominent. 
The Indian Ocean ? — Lamarck. 
3. SiDEROPORA suEDiGiTATA (Lamarck,) Blainville. — Lobato-ramulose ; 
branches short, subdigitate. Corallum with the stats sex-dentate ; interstices 
a little prominent and echinulate. 
The Indian or Austral Ocean. — Lamarck, 
4. SiDEROPORA PALMATA [Blainville). — Branches much compressed and 
thinner above, flabellate, sparingly digitate lobed, or subpalmate, often 1 to 2 
inches broad, and 3 to 5 lines thick at apex. Corallum having the cells slightly 
margined, and the columella a little prominent. 
East Indies. — Exp. Exp. 
5. SiDEROPORA MORDAX (Dana). — Branches nearly simple, much com- 
pressed, not thinner at apex, scarcely flabellate, i to 1 inch broad, and ^ an 
inch thick ; polyps with a pale yellowish disk, and short tentacles of a bright 
green color, deep brown at base. Corallum with the cells strongly vaulted, 
and the surface, therefore, decidedly scabrous. 
Plate 49, fig. 1, zoophyte, natural size ; 1 a, polyp, enlarged ; 1 6, cells of 
surface, at summit, enlarged.— Feejee Islands. — Exp. Exp. 
Genus III.— SEEIATOPORA. — Lamarck. 
Slenderly ramose ; branches and branchlets terete, polyps ver- 
tically more or less seriate, cells of corallum obsolescently rayed, 
not deep, and becoming filled and solid internally. 
1. Seriatopora subulata [Lamarck ). — In very ramose hemispherical 
clumps, branches quite stout (2 lines thick and at base sometimes 4 lines), 
