42 B. J. CHAPMAN ON THE 



Aulopora, Goldf., Sil, Dev., C!aib. 

 Reptellu, Rolle, Sil., Dev. 

 Cladoconus, McCoy, Carb. 



§ 2. Tabulata. 



The corals of this section are distinguished by the presence of numerous transverse 

 tabular in their component cells, coupled with the absence of r idiating' septa, or the rudi- 

 mentary, imperfect character of these when indistinctly present. They have been 

 separated widely in many systems, and have been allotted partly to the Alci/onaria, partly 

 to the Bryozou, and in part also to the Riigoi^it generally. Whilst thu.s manifestly occupy- 

 iug an uncertain position, the two fundamental characters given above — namely, the 

 presenci' of tabuLe, with absence or merely indications of septa — are sufficiently definite 

 to warrant their retention in a common group, and to show at the same time their 

 relations to the coral forms of section -1. in which botli tabula' and well developed septa 

 are present. Th(! more typical i-epresentatives, including all the better known genera, 

 may be arranged under six families, as in the following synopsis: 



Fam. 1. ClKclelidie : — No cceuenchyme Corallites, capilliform, or of small diameter, 



C/uctetes, Fisch. (including MonlicuUpora and Slenopora), Lr. 



Sil. to Trias. 

 Tetnidium, Satford. Lr. Sil. 



Fam. '1. Bedianoidithc : — No cteneuohyme. C'orallites comparatively large, polygonal, 

 with imperforate walls. 



Beaumontin, E. & H., Carb. 



Fam. o. Favuaiddte : — No coenenchyme. Corallites, polygonal, round or crescented at 

 surface, with perforated walls. 



G-roup A. Plant. — Tabulte horizontal or inclined : 



Favosites, Lmk., Sil., Dev., Carb. 

 Columnipora, Nich., Lr., Sil. 

 Alveolites, Lmk., Sil., Dev. 

 Pachypora, Linds., Sil. 

 Nodulipma, Linds., Sil. 



Group B. Timidi. — Tabula; convex or more or less vesicular : 



Emmonsia, E. & H., Sil., Dev., Carb. 

 ML'helinia, de Kon., Dev., Carb. 



Fam. 4. HalysUidie : — Corallites lubular, imperforate, connected only at opposite 

 sides, typically in chain-like aggregations. Tabuhe, horizontal : .: 



Halysiles, Fisch., Sil, 

 Thecostegiles, E. & H., Dev. 



