n the operculum
is closed). _Calcecla_, Lam. (In this Devonian genus there is a single
semicircular operculum furnished with a stout median septum and
numerous feebly developed secondary septa. The calyx is triangular in
section, pointed below, and the operculum is attached to it by
hinge-like teeth.)

AUTHORITIES.--The following list contains only the names of the more
important and more general works on the structure and classification
of corals and on coral reefs. For a fuller bibliography the works
marked with an asterisk should be consulted: * A. Andres, _Fauna und
Flora des Golfes von Neapel_, ix. (1884); H.M. Bernard, "Catalogue of
Madreporarian Corals" in Brit. Museum, ii. (1896), iii. (1897); * G.C.
Bourne, "Anthozoa," in E. Ray Lankester's _Treatise on Zoology_, vol.
ii. (London, 1900); G. Brook, "_Challenger_ Reports," _Zoology_,
xxxii. (1899) (_Antipatharia_); "Cat. Madrep. Corals," Brit. Museum,
i. (1893); D.C. Danielssen, "Report Norwegian North Atlantic Exploring
Expedition," _Zoology_, xix. (1890); J.E. Duerden, "Some Results on
the Morphology and Development of Recent and Fossil Corals," _Rep.
Brit. Association_, 1903, pp. 684-685; "The Morphology of the
Madreporaria," _Biol. Bullet_, vii. pp. 79-104; P.M. Duncan, _Journ.
Linnean Soc._ xviii. (1885); P.H. Gosse, _Actinologia britannica_
(London, 1860); O. and R. Hertwig, _Die Actinien_ (Jena, 1879); R.
Hertwig, "_Challenger_ Reports," _Zoology_, vi. (1882) and xxvi.
(1888); * C.B. Klunzinger, _Die Korallthiere des Rothen Meeres_
(Berlin, 1877); * G. von Koch, _Fauna und Flora des Golfes van
Neapel_, xv. (1887); _Mitth. Zool. Stat. Neapel_, ii. (1882) and xii.
(1897); _Palaeontographica_, xxix. (1883); (also many papers in the
_Morphol. Jahrbuch_ from 1878 to 1898); F. Koby, "Polypiers
jurassiques de la Suisse," _Mem. Soc. Palaeont. Suisse_, vii.-xvi.
(1880-1889); A. von Kolliker, "Die Pennatuliden," _Abh. d. Senck.
Naturf. Gesell_. vii.; * "_Challenger_ Reports," _Zoology_, i.
_Pennatulidae_ (1880); Koren and Danielssen, _Norske Nordhaus Exped.,
Alcyonida_ (1887); H. de Lacaze-Duthiers, _Hist. nat. du corail_
(Paris, 1864); H. Milne-Edwards and J. Haime, _Hist. nat. des
coralliaires_ (Paris, 1857); H.N. Moseley, "_Challenger_ Reports,"
_Zoology_, ii. (1881); H.A. Nicholson, _Palaeozoic Tabulate Corals_
(Edinburgh, 1879); M.M. Ogilvie, _Phil. Transactions_, clxxxvii.
(1896); E. Pr