A monograph of the British fossil corals - kreidefossilien.de

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BRITISH FOSSIL CORALS.
60. Genus Plesiastrea.
Milne Edw. and J. Haime, Comptes rend., t. xxvii, p. 49-1, 1848.
Corallum globose ; its under sm-face having the form of a naked costiilated plate.
Gemmation extra-calicular. Calices with a free margin, and a fossula rather shallow.
Columella spongy. Pali well developed, and corresponding to all the septa except those
of the last cyclum. Septa exsert, formed by a weU-developcd lamina, and having a delicately-serrated
apex. Costce and their dissepiments in general well developed.
Typ. sp., Plesiastrea Urvillii, Milne Edw. and J. Haime, Ann. des Sc. Nat., vol. x, tab. ix, fig. 2 ;
Astrea galaxea, Quoy and Gaim., Voyage de I'Astrolabe, Zooph., pi. xvii, figs. 10-14.
61. Gemis Leptastrea.
Milne Edw. and J. Haime, Comptes rend., t. xxvii, p. 494, 1848.
Corallum very dense and incrusting, and increasing by fissiparity, as well as by
extra-calicular gemmation. Costal cceuenchyma quite compact. Calices in general much
crowded together, but preserving then- margins distinct. Columella papillose. Sqjta thin,
closely set, exsert, delicately granulated, and having their apical margin almost entire near
the walls, but delicately denticulated towards the columella. Dissepiments not very abundant.
CostcB rather indistinct.
Typ. sp., Leptastrea Roissyana, Milne Edw. and J. Haime, Ann. Sc. Nat., 3"' serie, vol. x, tab. ix, fig. 6.
62. Genus Solenastrea.
Milne Edw. and J. Haime, Comptes rend., t. xxvii, p. 494, 1848.
Corallum forming in general a convex mass, of a light and cellular structure. Gemmation
extra-cahcular. Curallites long, slender, and united by an exothecal structure,
and not by the costcR, which do not meet, and are often rudimentary. Calices circular,
with an exsert margin. Columella spongy, and in general smaU. Se^ita very thin ; their
margin denticulated. Dissepiments simple, numerous, and closely set.
Typ. sp., Solenastrea Turonensis, nob. ; Astrea Turonensis, Michelin, Icon., pi. Ixxv, figs. 1, 2.
63. Genus Phymastrea.
Milne Edw. and J. Haime, Comptes rend., t. xxvii, p. 494, 1848.
Corallum forming a convex or a horizontal mass. Corallites prismatical ; sm-rounded
from top to bottom by a thin epitheca ; very nearly approximated to each other, but not
united by their walls, and cemented together by means of a certain number of large
wart-like processes, so as to leave an empty space between them. Gemmation extracalicular.
Calices sub-polygonal, with a free margin. Columella spongy, well developed.
Septa large, slightly exsert, and strongly dentated. Walls thick ; no trace of costse.
Typ. sp., Phymastrea Valenciennesii, Milne Edw. and J. Haime, Ann. Sc. Nat., 3"" serie, vol. x,
tab. ix, fig. i.