no BRITISH FOSSIL CORALS. 



By an attentive examination of Goldfass's corals in the Poppelsdorf Museum, and in 

 the cabinet of Professor Bronn, at Heidelberg, we have been able to ascertain that the 

 Astrea sexradiafa, Goldfuss,^ belongs to this small group, but the specimen figured is in a 

 very bad state of preservation. The genus Convexastrea contains, therefore, at present 

 three species, and the one here described differs principally from the two others by the less 

 regular form and the thickness of the septa, and by these laminse being less exsert. 



Family ASTREID/E, (p. xxiii.) 

 Genus Montlivaltia, (p. xxv.) 



1, MoNTLiVALTiA Smithi. Tal). XXI, figs. I, \a, \h. 



Madrepora turbinata, Smith, Strata identified by Organic Fossils, p. 84, tab. Upper Oolite, 

 fig. 3, 1816, (appears to be a specimen, the wall and the basis of which have been worn 

 away.) 



Corallnm simple, short, fixed by a large basis, which is somewhat expanded. Wall a 

 little constricted near the basis, and covered with a thick epitheca which extends to a short 

 distance from the calicular margin. Calice regularly circular ; fossula not very deep, but 

 well defined. In general five complete cycla of septa, but sometimes the last cyclum is 

 quite rudimentary in one half of each system. The septa are exsert, very strong, broad, 

 quite straight, and very closely set. Those of the first three cycla are almost of the same 

 size, and extend to the centres of the visceral chamber ; those of the fourth cyclum are 

 also large, and those of the last cyclum are much smaller, but remain always free from any 

 adherence at their inner edge. The lateral surfaces of the septa appear to be strongly 

 striated, and their upper edge was probably denticulated originally, but had become quite 

 smooth by wear in the two specimens here described. Diameter of the calice one inch 

 three Ihies ; height, seven lines in one specimen, and more than an inch in the other. 



These corals were found near Bath and communicated to us by Mr. Pratt. The fossil, 

 which appears to belong to the same species, and is figured in Mr, Smith's work, was found 

 at Farley. 



Montlivaltia Smithi differs from most of the other species belonging to the same genus 

 by the thickness of its sejjta and its broad, short form. It resembles most our M. Wric/hti^ 

 but this fossil does not appear to have been fixed by a large basis, and its septa are more 

 numerous and more unequal in size. 



* Petref. Germ., vol. i, tab. 24, fig. 9 ; Convexastrea sexradiatu, Milne Edwards and J. Ilaimc, Polyp. 

 Palscoz., etc., p. G.3. 



2 Tab. xxvi, fig. 12. 



