TRIBE III. MADREPORACEA. 
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26. Manopora planidscdla {Dana).- — Glomerate, incrusting, nearly plane 
above ; interstices 1 to 1| lines broad, a little convex. Corallum porous ; 
cells deep, rather indistinctly 12-rayed. 
Plate 47, fig. 3, corallum, natural size ; 3 a, vertical section, enlarged.— 
Feejee Islands. — Exp. Exp. 
27. Manopora foveolata [Dana). — Glomerate, incrusting, nearly plane 
or a little undulate above. Corallum profoundly alveolate, the radiated cells 
situated at the bottom of deep pits a line broad ; interstices very thin and 
sometimes subacute. 
Probably the Feejee Islands. — Exp. Exp. 
28. Manopora digitata (Dana). — Small, ramose, often digitate, branches 
subterete, somewhat compressed, often tortuous, J of an inch thick, subequal, 
obtuse ; polyps yellow, tentacles short, equal. Corallum quite smootli, cells 
immersed, one-sixth of a line broad. 
Plate 48, fig. 1, zoophyte, natural size; I a, polyp, enlarged; 16, extremity 
of branch, natural size ; 1 c, cell and surface around, enlarged ; 1 c/, part of 
transverse section of branch, enlarged. — Feejee Islands. — Exp. Exp. 
29. Manopora tortuosa [Dana). — Ramose, branches often 4 inches long, 
I of an inch thick, curved or tortuous, subterete, somewhat compressed. Co- 
rallum quite smooth, cells immersed, i of a line broad. 
Plate 48, fig. 2, corallum, natural size.— Singapore, East Indies. — Exp. Exp. 
Family II.— FAVOSITID.^. 
Polyps intermittedly coralligenous at base, cells, tlierefore, 
solid at bottom, and internally the corallum cells crossed by 
septa, or quite closed by tlie secretions ; calicles none. 
The Favositidge may be divided into three subfamilies : — 
1. Alveoporin^e. Cells contiguous, slenderly echinulate within; parietes 
cribrate. 
2. Favositin^. Cells contiguous, at the summits at least; rays entire or 
obsolete. 
3. Helioporina:. Cells in no part contiguous, circular. 
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