ADDENDA. 113 
concentricis instructis. Area cardinis angusta, elongata, foveolis (8) latis, subcon- 
cavis. 
Shell subequilateral, moderately convex, slightly arched longitudinally in the left 
valve ; test thick, umbones acute and prominent; anterior border straight ; hinge-border 
moderately lengthened, straight, sloping obliquely downwards. Hinge-area narrow, 
elongated, pits (8) wide, and only slightly concave; lamelle of growth large and 
irregular. 
Length, about twice as great as the transverse measurement ; diameter through the 
valves, one third of the length. 
Geological Position and Locality. he Forest Marble of Gastard; in the cabinet of 
W. Walton, Esq. 
Pecten sussprinosus, Schloth. Tab. XL, fig. 14. 
Pecren sussprinosus, Schloth. Petref., p 223. 
— — Goldfuss. Petref., t. 90, fig. 4. 
= — Quenst. Der Jura, p. 500, pl. 67, figs. 3,4; and pl. 92, figs. 
ay Ai 
Testa ovato-orbiculari fornicata equivalvi, costis (12) equalibus elatis subacutis in dorso 
spinosis, sulcis conformibus transversim lineatis, auriculis inequalibus costatis lineisque 
decussantibus striatis. (Goldfuss.) 
Shell ovately orbicular, equivalve ; coste (12) large, elevated, subacutc, each having 
upon its ridge a few short spines; the interstitial suleations are narrow, with delicate, 
transverse lines ; the auricles are unequal, the anterior auricle of the right valve being the 
larger ; they have radiating and decussating lines. The valves have but little convexity ; 
the radiating costee form one third of a circle. 
Height, 7 lines; transverse diameter, 9 lines. 
Geological Positions and Localities. The Forest Marble of Locus and Farleigh, 
Somerset; in the collection of W. Walton, Esq. The foreign localities cited by Professor 
Quenstedt are Bopfingen and Waldenburg, in the Parkinsoni Oolite and the Bradford 
Clay ; also Nattheim, in the Coralline Oolite. 
Macropon Hirsonensis, var. RuGosA. Tab. XXXVI, fig. 9. 
The Forest Marble of Wilts and Somerset has this species in the form of a variety 
which is distinguished from the shell of the Inferior and Great Oolite by the following 
features :—It has greater convexity, a wider hinge-area; the posterior side is more de- 
pressed, and is not uncommonly traversed by two or three radiating furrows, and is in 
some instances separated from the other portion of the surface by a distinct keel. The 
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