a. G. Carruthers — A Revision of some Carboniferous Corals. 21 



of that formation, by the vigorous revival of zonal work -witnessed 

 in the last few years. Those species in most urgent need of revision 

 belong to the lower, or Tournaisian division of the Limestone, since 

 their satisfactory determination affords a basis for evolutionary studies 

 on the succeeding faunas, and an attempt is here made to deal with 

 a few of these forms. 



The great French actinologists were compelled, in the absence of 

 opportunities for slicing and microscopic investigation, to confine their 

 attention to the external characters of their specimens, assisted 

 occasionally by such rough vertical sections as could be obtained 

 by fracture. This also was the case in what appears to be the only 

 authoritative re-description of their species, published in 1870 by 

 M. de Koninck, in his well-known volume entitled " Nouvelles 

 Recherches sur les Animaux Fossiles du Terrain Carbonifere de la 

 Belgique." Indeed, in the introduction to that work, M. de Koninck 

 expresses regret at his inability to take advantage of the newer 

 methods of research then being inaugurated. The older authors were 

 not enabled, therefore, to completely define their species ; for obviously 

 the internal, as well as the external, structures must be determined 

 before an adequate idea of the nature and relationships of these corals 

 •can be gained. Indeed, of the two, the internal structures are the 

 more important, since, until they are known, the meaning and value 

 of the chief external feature, the calyx, cannot be duly appreciated. 



For the elucidation of these internal structui'es, great use has been 

 made, in the present investigation, of serial transverse sections. 

 Such treatment is entirelj^ necessary, if reliable conceptions on these 

 points ai'e to be gained ; by this means the progressive changes 

 occurring during the growth of the coral are ascertained, specific 

 differences are more correctly gauged, and, most important of all, the 

 phylogenetic nature of various structures realised. It is true that the 

 exigencies of space can rarely permit of such sections being illustrated 

 in their entirety ; that is, indeed, the case in the present instance, but 

 the results obtained can, at any rate, be embodied in the text. 



For a re-description of species to be of any value, it is evident that 

 if paratypes are not available (i.e. examples named by the authors 

 themselves), then, at any rate, the specimens used should resemble the 

 originals in nature and preservation as closely as possible, and should 

 be derived from the same locality (i.e. they should be topotypes) ; 

 these conditions are fulfilled in the present case. 



The holotypes of the species to be immediately described were 

 collected from Tournai and sent by de Koninck ^ to Milne-Edwards 

 and Haime for description in their "Polypes Fossiles." In his own 

 work (the " Nouvelles E-echerehes"), published thirty years later, 

 de Koninck dealt with similar material from this locality, whence 

 also the specimens on which the present account is based (the majority 

 forming the Piret Collection at the British Museum) have also been 

 derived. These corals are silicified ; the exquisite preservation of 

 most of their calices resembles that of recent corals far more than 

 those of Palaeozoic age. 



^ With the exception of Michelin's Canmia cornucopi(S and Can'mia cornu-bovis, 

 which, however, also came from Tournai. 



