298 BRITISH FOSSIL CORALS. 



are much smaller and less irregular, and the lateral circular accretion ridges are much less 

 developed. Height about 2 inches, diameter of the calice If inch. 



Dudley. Collection of the Geological Society, of Mr. Fletcher, Mr. John Gray, &c. 



3. Cystiphyllum siluriense. Tab. LXXII, figs. 1, la. 



Cystiphyllum siluriense (pars), Lonsdale, in Murchison, Sil. Syst., p. 691, pi. xv bis, 



1839. (Not the fig. 2, which is an Omphyma.) 

 Cyathophyllum vesiculosem, Eichwald, Sil. Syst. in Esthl., p. 201, 1840. 

 Cystiphyllum siluriense, Milne Edwards and Jules Haime, Pol. Foss. des Terr. Palseoz. 



(Arch, du Mus., vol. v), p. 465, 1851. 



Corallum turbinate, short, and very broad ; epitheca thick, and presenting some radici- 

 form prolongations. Calice subcircular, rather deep, very broad, presenting some obscure 

 indications of septal stria?, and occupied by large unequal vesicles, the structure of which 

 is very distinct in a vertical section. Height about 1|- or 2 inches; diameter of the calice 

 somewhat more. 



Wenlock. Dudley (Lonsdale) ; Ardaun and Cong (M'Coy) ; Russia (Eichwald). 



Collection of the Geological Society of London. 



The Silurian fossil described by Professor M/Coy, under the name of Fistulipora 

 decipiens? much resembles a Heliolites, in which all traces of the septal apparatus have 

 disappeared, and the ccenenchyma does not present the vesicular structure which is charac- 

 teristic of the genus Fistulipora, but is made up of small vertical tubes, divided like the 

 visceral chambers by numerous horizontal tubulse. 



The same palaeontologist has recently added to the list of the British Silurian Corals, 

 two other species, the zoological characters of which are still so imperfectly known, that 

 we cannot give any decided opinion respecting their natural affinities. One of these, 



1 M'Coy, Ann. and Mag. of Nat. Hist., 2d ser., vol. vi, p. 285, 1850; ibid., Brit. Palseoz. Foss., 

 p. 11, pi. ic, fig. 1, 1851. 



" Corallum forming hemispherical or sub-cylindrical masses, three or four inches in diameter, con- 

 centrically wrinkled at base ; cell-tubes straight, sub-parallel, with moderately thick walls, leaving clearly 

 definite, circular, smooth-edged cells in the transverse section, very regular in size and disposition ; usually 

 slightly less than half a line in diameter, and averaging rather less than their diameter in the shortest line 

 between adjacent cells, in which line there are usually two, or more, rarely three, of the intermediate 

 vesicular cellules ; about eighteen of the intermediate or polygonal cellules in the snace of two lines ; 

 diaphragms in the small tubes slightly more or less than their diameter apart, two inteiiiaphragmal spaces 

 in the large tubes slightly exceeding the diameter. 



" Wenlock Limestone, near Aymestry, Herefordshire." (M'Coy, op. cit.) 



