324 PROCEEDINGS OF THE GEOLOGICAL SOCIETY. [April 9, 



Cypricardia brevis, Wright, nov. sp. 



Shell triangular, inequilateral, ventricose, and cordate ; posterior 

 side short and sharply angular ; anterior side bluntly rounded ; urn- 

 bones large, prominent, nearly central and much recurved, with an 

 acute carina descending from them to the posterior side; surface 

 nearly smooth, slightly marked with lines of growth ; margin of the 

 valves straight. 



A. Frocester specimen. — Breadth 1 ^^ inch. Length 1^ inch. 

 Thickness 1 ^^ inch. 



B. Sherborne specimen. — Breadth 23^ inches. Length 2^^ inches. 

 Thickness ly^^- inch. 



Affinities and differences. — This shell resembles Cypricardia 

 Bathonica, d'Orbigny, but it is a much shorter and straighter form ; 

 the carinse on the posterior side are more prominent and acute ; but 

 it wants the graceful twisted slope which characterizes C. Bathonica. 



Locality and stratigraphical position. — I have collected this 

 species out of the fossiliferous nodules at the base of the Sands at 

 Nailsworth, and in the Upper Lias Sands at Frocester Hill, Ammo- 

 nites bifrons being associated with it in the same nodule ; much 

 larger specimens are found in the Upper Lias near Sherborne. It 

 appears to be a very rare shell. 



Opis carinatus, Wright, nov. sp. 



Shell trigonal, its breadth nearly equalling its length ; umbones 

 large and incurved, bounded on their posterior borders by acute 

 prominent carinas which descend along the margin of the valves and 

 bound the posterior side ; anterior side rounded ; surface of the 

 valves ornamented with regular concentric ridges ; posterior side 

 concave, the surface marked with sharp oblique close-set lines ; 

 lunule small, nearly circular. 



Length ly% inch. Breadth \-^ inch. Thickness -|-|ths of an 

 inch. 



Affinities and differences. — This shell resembles Opis (Astarte) 

 triffonalis, Sow., in its proportionate length ; but it is distinguished 

 from it by the regular concentric ridges on the surface of the valves, 

 those on O. triffonalis being waved, by its acute prominent carinae, 

 and by the general sharpness in the outline of the different parts of the 

 shell. It differs from Opis lunulatus, Sow., in being a much longer 

 and more compressed form, in having more prominent carinae and a 

 small shallow and nearly circular lunule, that of Opis lunulatus 

 being large, deep, and cordate, with acute margins. 



Locality and stratigraphical position. — Collected only from the 

 Cephalopoda-bed of Frocester Hill ; it is not an abundant shell, and 

 is seldom well preserved. 



Cardium Hullii, Wright, nov. sp. 



Shell smooth, subtrigonal, inequilateral ; breadth nearly equalling 

 its length ; the anterior side convex and rounded ; the posterior side 



