180 PERMIAN FOSSILS. 



Cardiomorpha modioliformis, King. Plate XIV, figs. 18, 19, 20, 2), 22, 23. 



Plel'rophorus modiolifokmts, King. De Verneuil, Ball. Soc. Geol. de France, 2™' serie, 



t. i, p. 32, 1844. 

 — — „ Geol. Russ., vol. i, p. 224, 1845. 



Cardiomorpha — „ King, Catalogue, p. 10, 1848. 



Myoconcha — „ Howse, Trans. T. N. F. C, vol. i, p. 245, 1848. 



Diagnosis. — Modioliform : tumid diagonally in the unibonal region, and compressed 

 towards the margins : measuring three quarters of an inch from the point of the 

 umbones to the posterio-ventral margin : marked with rather distant lines radiating 

 from the umbones posteriorly, the lines being raised in young individuals, and impressed 

 in old ones. Umbones incurved. Lunette heart-shaped. Corselet long, rather shallow, 

 defined by a rather prominent ridge, which curves in both valves from the point of the 

 umbone to the termination of the hinge. Anterior muscular impressions bounded pos- 

 teriorly by a sHghtly elevated ridge. 



Cardiomorpha modioliformis, in its marginal outline, bears a resemblance to some 

 varieties of Cardiomorpha Pallasi {Mytilus id}), De Verneuil ; but it is a shorter and a 

 more tumid species ; and its umbones are more incurved : in the latter character, and 

 in being diagonally tumid, it approximates to Cypricardia glahrata, Phillips, — a species, 

 which, had it occurred in the Permian rocks instead of the Carboniferous, I might 

 have considered identical with the present one. It has very much the aspect of a 

 Modiola, particularly one variety, which is distinctly lobed in front (vide PI. XIV, 

 figs. 20, 23). Old specimens occasionally become diagonally carinated like Cypricardia 

 rhombea, Phillips (vide PI. XIV, fig. 21). The specimen represented by the figure last 

 cited, the largest one I have procured, is upwards of an inch in width. 



It occurs, but rarely, in the Shell-limestone of Tunstall Hill, Ryhope Field- 

 House-Farm, and Humbleton Quarry. 



Genus Fleurophorus, King, 1848. 



Diagnosis. — " Form inequilateral : cartilage external : anterior adductor muscular 

 impressions deeply excavated, often bounded posteriorly by a ridge : pallial line entire : 

 dentition cardinal and posterior : cardinal teeth two in each valve, diverging inwardly, 

 and interlocking alternately : posterior teeth linear ; the receiving tooth in the left 

 valve." (King.') 



Type, Area costata. Brown. 



^ A specimen of this species, kindly given me by M. de Verneuil, clearly exhibits the external position 

 of the cartilage fulcra, a character which has not been overlooked by its founder (vide Geol. Russ., vol. ii, 

 p. 316) : it is therefore clearly neither a Mytilus nor a Modiola. 



2 Catalogue, p. 11. 



