38 SUPPLEMENT TO GREAT OOLITE MOLLUSCA. 



Perna foliacea, Lye. Tab. XXXVII, figs. 3, 3 a. 



Testa atnpla subaquivalvi, subplana, umbonibus proniinulis acutis ; latere antico 

 excavato, margine 'posterior e et inferiori elliptico curvato ; lateribus rugis concentricis 

 paucis irregularibus. Foveolis interni ignotis. 



A large, subajquivalve, depressed shell, with prominent, pointed umbones, excavated 

 and thickened anterior border, the hinge-line short, the posterior and inferior borders 

 elliptically rounded, the general figure being mytelliform, the left valve being somewhat 

 more convex than the other ; the test is thin, with delicate margins. 



Dimensions. Length, 4^ inches ; opposite diameter, 2^ inches ; the hinge-area has 

 not been exposed. 



Geological Position and Locality. The Great Oolite of Minchinhampton Common ; 

 a single fine specimen of each valve is in the collection of the author, who is not cognizant 

 of any other examples. 



Inoceeamus quadratus, Sow.f sp. Tab. XXXVIII, figs. \,\ a, \ b. 



Perna quadrata, Sow. Min. Con., t. 492, non Phil, non Goldf. 

 — — Lycett, Ann. and Mag. Nat. Hist., 1855. 



Testa tenue subquadrata, transversa, inaquivalvi, valde inaquilatera, valva sinistra 

 antice oblique injlato, postice compresso ; umboni viagno, subinvoluto, antrorsum instructo ; 

 linea cardinali subliorizontali elongato ; latere anteriore truncato, infra umbonem concavo, 

 basi subrecto, superficie rugis concentricis paucis irregularibus. Valva dextra planata 

 umboni parvo antico. Foveolis interni parvis numerosis. 



Shell thin, subquadrate, transverse, inequivalve. The left valve inflated anteriorly, 

 with a large, subinvolute, projecting beak, and a steep, truncated and excavated slope 

 beneath it ; the posterior side is very thin, compressed, and expanded ; the hinge-line is 

 lengthened and nearly horizontal ; the base is lengthened and nearly straight. The right 

 valve is flattened ; the umbo is small, pointed, and anterior. The internal hinge-pits are 

 placed upon a narrow, lengthened plate ; they are small and numerous. The surfaces of 

 the valves are smooth, with a few irregular, concentric plications. 



The diagnosis in the ' Mineral Conchology ' is as follows : — " Quadrilateral, one side 

 shorter than the other three; valves gibbose, unequal, the shorter side very concave, 

 bounded by two obtuse carinse." 



The figure in the ' Mineral Conchology ' has the right or smaller valve facing the 

 spectator ; the contour of the larger or convex valve is not seen ; even the outline is not 

 perfect, as there seems to be a portion of the lower (right) border wanting, and thus 

 forming an angle at its anterior extremity, which would be rounded in the perfect shell; 

 but the whole is stated by the author to be little better than a cast. With such an 



