222 TABULATE CORALS. 



to appear for the first time in the Lower Silurian period, and 

 is well represented in the Upper Silurian. In the Devonian 

 period it attains its maximum of development, and a few Car- 

 boniferous species are known ; but the latter are rare and local 

 in their distribution, and the genus is not known to have sur- 

 vived into the Permian period. 



The genus Cladockonus, M'Coy, was proposed in 1847 (Ann. 

 and Mag. Nat. Hist., ser. i, vol. xx. p. 227) for some Aus- 

 tralian Palaeozoic corals, having " some relations to Aulopora" 

 but differing " in their curious erect habit, regular angular mode 

 of branching, slender, equal, stemlike tubes, and abruptly-dilated 

 terminal cups bent in nearly opposite directions." He further 

 states that the curious little Carboniferous corals which he had 

 formerly referred to Lamoroux's genus Jania (Syn. Carb. Foss. 

 of Ireland, 1844) are really to be placed in the genus Clado- 

 ckonus. There seems, further, to be no reasonable doubt that 

 the genus Pyrgia, Edwards and Haime (Pol. Foss. des Terr. 

 Pal., p. 310, 1851), is really founded upon forms of Cladockonus, 

 M'Coy, and that it must therefore be withdrawn in favour of 

 the latter. My friend Mr R. Etheridge, jun., and myself have 

 prepared a paper 1 dealing with the structure and relations of 

 some of the forms of Cladockonus, and we find that besides 

 species which may be retained in Cladockonus, the genus con- 

 tains at least one very peculiar type (viz., C. crassus, M'Coy), 

 which must be considered as generically distinct, and to which 

 we have given the name of Monilopora crassa, M'Coy, sp. In 

 a typical species of Cladockonus, such as the Carboniferous C. 

 (Pyrgia) Michelini, E. and H., the corallum has the form of a 

 slender erect branching colony, composed of long conical coral- 

 lites (fig. 31, A and B), which are produced from one another by 

 lateral budding, the entire growth being fixed basally to some 

 foreign object by one or more isolated points of attachment. 

 An excellent description of this singular coral is given by De 

 Koninck (Nouv. Rech. sur les An. Foss., p. 153, PI. XV., fig. 



1 Since the above was written this paper has been published (see Geol. Mag., 

 Dec. ii. vol. vi., July 1879). 



