82 PROCEEDIXGS or THE GEOLOGICAL SOCIETY. [DcC.G, 



hollowed out below ; both ears have radiating costae and transverse 

 striae. Umbonal angle 110°-115°; length 2| inches ; breadth equals 

 length. 



Locality and position. — Sutton and Southerndown series at Sutton. 

 Yery abundant. 



The exterior structure of the shell is frequently badly preserved ; 

 the concentric striations are then lost, and many of the smaller ribs, 

 but their alternate character remains generally more or less plain. 



Affinities. — This shell is most nearly allied to P. Valoniensis (or 

 Lugdunensis, Michelin) ; it agrees with it and P. Bavaricus, Winkl., 

 and P. Favrii *, Stopp. (all Rheetic species), in the characters of the 

 lateral areas, but with neither of them in the character of the ribs. 

 In general form and alternate arrangement of ribs it resembles P. 

 Schroeteri, Giebel, from the Muschelkalk ; but that species has not the 

 obliquely marked areas. 



Some specimens of P. Valoniensis show a much greater resemblance 

 than others to this species. 



5. Pecten", sp. 



Another orbicular Pecten I am unable to describe, having only one 

 imperfect specimen, the umbo being wanting. It is distinguished by 

 elevated strong concentric striae in the interspaces between the ribs. 

 It has a slight resemblance to P. cequivalvis ; but the ribs are more 

 numerous, narrower, and less regular than in that species ; this shell 

 is also much smaller. 



6. Lima ttjbercflata, Terquem. 



Shell moderately convex, suboval, slightly inequilateral. Bibs 

 1 1-1 2, narrow, radiating, bearing occasionally tubercles or remains 

 of spines ; the ribs slope away gradually into the interspaces, which 

 are broad. Surface with concentric, more or less rugose laminae. 

 Posterior ear larger ; anterior ear gaping below, somewhat plicated. 

 Hinge-line straight. No lunule. Length 2^ inches ; breadth ^ths 

 of length. 



Locality and position. — Sutton and Southerndown series and Lias 

 at Bridgend. 



This species is most nearly allied to L. pectiniformis of the Inferior 

 Oolite, but is much smaller and less rugose. It corresponds entirely 

 with the description of Terquem's species L. tuberculata (Mem. de la 

 Soc. Geol. de France, vol. v. 2nd series, 1855). I have not hesitated, 

 therefore, to identify it with that species. It was described from the 

 Infralias (Planorbis- and Angulatus-beds) of Luxembourg, and 

 has been noticed by Renevier from the Rhsetic beds of the Canton 

 de Yaud (Bull, de la Soc. Yaudoise des Sciences Nat. vol. viii. 

 p. 34) ; from the Infralias of the Department of Cote d'Or by 

 Martin (Mem. de la Soc. Geol. de Prance, 2nd series, vol. vii.) ; and 

 I have also found it in the Planorbis-beds near Bridgend. 



* This name seems preoccupied, having been given to another shell by M. 

 d'Archiac (1854) ; Stoppani's name must therefore be cancelled, and I propose 

 to substitute for it the specific name of Beneviei-i. 



