88 



PROF. P. MABTIIS^ DTJNCAN'S EEVISIOIf OF THE 



The columella is spongy, essential, and well developed. The septa 

 are stout and exsert, and their dentations are close, subequal. 



Distribution. — Fussil. Cretaceous: Europe. Eocene: Asia. — 

 decent. Caribbean Sea, Bermuda, and Chinese seas. 



G-enus Stiboria, Etallon, LetlicEa Bruntrutana (Zurich 1864i), 



p. 386. 



Colony massive, adherent by a small surface, and in the form 

 o£ thin laminae. Corallites in" short series, which are more or less 

 flexuous, united below, and separated above by a groove on top 

 of tlie intercalicular ridge. Eidge resulting from the incomplete 

 fusion of the corallite-walls. Calicinal centres indistinct. Co- 

 lumella absent. Septa dentate near the axis. An epitheca exists 

 covering costae of the common plateau. 



Distrihution:- — Fossil. Oolitic: Europe. 



Grenus MANiciisrA, Flirenherg^ amendedhy Milne-Fdwards ^ Jules 

 Haime, Hist. Nat. des Corall. vol. ii. p. 397 (1857). 

 Colony massive, free or pedunculate, broad-based, subhemi- 

 spherical, tall, and convex or subcorneal or short. Corallites 

 M'ith their walls fused with those of their neighbours, except 

 in young forms. Calicinal valleys long, broad and deep, united 

 by simple or broad and furrowed collines. Calices with indistinct 

 centres. Columella spongy, essential. Septa close, thin, strongly 

 granulated laterally, the principal with a paliform lobe, and with 

 the free edge divided by fine teeth, which are regular, close, and 

 largest near the columella. The common plateau is furnished 

 with costse, which are delicate and dentate, and are partly covered 

 by an epitheca, which is readily detached. Endotheca abundant, 

 unequal. 



Distribution. — Becent. Caribbean Sea. 



Genus M^andrina (pars, Lamarch), Milne-Fdwards Sf Jules 



Saime, Hist. Nat. des Corall. vol. ii. p. 388 (1857). 

 Colony massive, dense, convex, gibbose, subplane or subsphe- 

 roidal, largely fixed by its base. The series of corallites unite by 

 their walls, which are compact, and j)roduce long, simple ridged 

 collines. The valleys are sinuous, long, but vary in length, depth, 

 breadth, and meandroid nature. Calices mostly indistinct, some 

 may be circumscribed. Columella formed by masses of spongy 

 tissue well developed. The septa are close, parallel, their inner 

 edge thickened and enlarged transversely ; upper margin denti- 



