A monograph of the British fossil corals - kreidefossilien.de

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xxxvi
BRITISH FOSSIL CORALS.
Section IL—ASTREINtE CONFLUENTES.
Corallum massive, increasing by fissiparity, and formed by a series of corallites, the
individuality of which is not distinct. The calices, thus united in a common trench, have
their septa aiTanged in a parallel manner in two lines ; and the columella, when existing,
is continuous in the whole length of the series.
These meandriform Corals much resemble the confluent Eusmilinse, and in fossils where
the apical teeth of the septa may be worn away, it is often diificult to distinguish them. It
may therefore be useful to mention that, in the confluent Astreinse, the gyri are always completely
united laterally, and never more or less segregate, which is sometimes the case with
the confluent Eusmilina? ; that the columella, which is generally spongy in the latter, never
presents that loose structure in this section ; and when it is lamellar, the septa are united to
it by an undivided margin in the confluent Eusmilina3, and by a series of trabicula; or
processes in the confluent Astreinse ; lastly, that the sides of the septa are more or less
granulated in all these Astreina;, and are on the contrary almost glabrous in the meandroid
Eusmilinae.
48. Genus Meandrina.
{Pars) Lamarck, Hist, des Anim. sans Vert., t. ii, p. 244, 1816 ; Milne Edw. and J. Haime, Comptes rend.,
t. xxvii, p. 493.
Corallum glomerate, adherent by a very broad basis, and having a very dense
structure. Gyri intimately united by their lateral walls, which constitute simple, compact
ridges, with a cristate apex. Calicular trenches very long. Columella much developed,
spongy and essential (that is to say, not arising from the septa, and distinct from the
bottom of the visceral chamber). Sepia crowded, enlarging near the columella, and not
presenting any appearance of a paliform lolie. Plale or exterior common walls of the
corallum covered with a complete delicate epitheca.
Typ. sp., Meandrina filogruna, Lamarck, loc. cit., vol. ii, p. 248 ; Michelin, Icon., pi. xi, fig. ~
49. Genus Manicina.
{In parte) Ehrenberg, Corall. des Roth. Meeres, p. 101, 1834; Dana, op. cit., p. 188, 1846; Milne Edw.
and J. Haime, Ann. des Sc. Nat., vol. xi, p. 285, 1849.
Corallum free or sub-pedicellate, in the adult state ; sub-turbinate when young, but
becoming convex, and massive. Gpi very long, and united by their walls, so as to
form simple ridges, as in the preceding genus ; the apex of the ridge cristate or sulcate.
Calicular trench broad and deep. Columella spongy, and even more developed than
in Meandrina. Sei^la thin, crowded, strongly granulated, and armed with delicate, equal
teeth ; a well-characterised pahform lobe arising from the edge of the principal septa
near the columella. Plate or exterior common wall covered with thin and very delicatelyserrated
costffi ;
its infeiior part having an incomplete epitheca.
Typ. sp., Manicina areolatu, Elirenberg, loc. cit. ; Madrepora areolata, Ellis and Solander, op. cit.,
tab. xlvii, fig. ,5.