98 PALEOZOIC CORALS AND FORAMINIFERA. 



in that species, their small diameter compared with their cups 

 distinguishes it from the C. crassa (M^Coy) of the carboniferous 

 slate of Ireland. 



Rare in the carboniferous limestone of Derbyshire. 



{CoL University of Cambridge.) 



(Madreporacea.) 



Dendropora megastoma (M^Coy). 



Bp. Char. Stem slightly flexuous, subquadrate, branches few, 



distant, resembling the main stem in size and shape, and 



coming off from it nearly at right angles ; each face has a row 



of large oval cells with prominent edges, the sides of which 



have twelve vertical sulci ending in tubercles ; the cells of each 



row are rather less than twice their diameter apart, the lateral 



rows opposite, alternating with the other two rows ; the width 



of the cells slightly exceeds that of the face on which they 



rest, so as to indent the margin ; interstices obscurely poroso- 



punctate ; width of stem about half a line. 



This beautiful coral is distinguished from the D. explicita 



^Mich.) from the Devonian beds of Boulogne-sur-Mer by its 



smaller size and larger cells. Michelin, in his ' Iconographie 



Zoophytologique,^ founds this genus from the last-named coral, 



and approximates it to the genera Criserpia and Aulopora ; the 



twelve sulci which I observe to the margin of the cells in this 



species however show that this cannot be the true affinity of the 



group, which must now rather be placed in the Madreporacea 



near Seriatopora. 



I have examined several specimens on a piece of carboniferous 

 limestone from Derbyshire. 



[Col. University of Cambridge.) 



Palceopora (M^Coy), n. g. 

 Gen. Char. Corallum polymorphous, generally subhemispherical 

 and concentrically ridged beneath, rarely branched ; formed of 

 cylindrical, distinctly walled, tubular cells, having internally 

 twelve vertical sulci or rudimentary lamellae, and divided at 

 irregular intervals by transverse diaphragms ; the tubes sur- 

 rounded and connected by a uniform minute network of small 

 vesicular plates. 



I propose this genus for all the so-called Porites of the palaeo- 

 zoic rocks. First described by Goldfuss as As trace, they were re- 

 moved by Ehrenberg (Ueber Corallenthiere des rothen Meeres, 

 &c.) and Lonsdale (Silurian System) to the recent genus Porites, 

 in which they were followed — probably without examination — by 

 many writers ; Profs. Bronn (Lethsea, &c.), Phillips (Palaeozoic 

 Fossils) and others have however much more happily pointed out 



