256 PROCEEDINGS COTTESWOLD CLUB 191 1 



never to attain the size of the average example of G. scarbur- 

 gensis. Moreover the hinge-margin is relatively longer than in 

 G. acuta, the ratio hinge-line /length being about -57 for G. 

 scarburgensis whereas it is -46 for G. acuta. 



It is aUied to Gervillia prcelonga Lycett and G. subcylindrica 

 Morris and Lycett, from both of which it is distinguished by 

 its greater height, its broad posterior portion, and the greater 

 convexity of its ventral margin. 



The right valve figured by Phillips {loc. cit. supra) from 

 the Scarborough Limestone belongs to this species, though 

 Phillips' figure makes the shell appear rather too cylindrical. 

 Several specimens in York Museum which were named Ger- 

 villia acuta Sow., by Philhps have been examined and compared 

 with the types of G. scarburgensis, but it has not been possible 

 to identify any particular specimen as that actually figured by 

 Phillips. 



Miinster (in Goldfuss) appears to have recognised the 

 difference between Gervillia acuta Sow. and Phillips' inter- 

 pretation of that species, for he cites " Gervillia acuta, Philhps " 

 as synonymous with his G. lanceolata.^ (Petref. Germ., p. 123, 

 tab. cxv., fig. 9). The latter species, however, cannot be 

 regarded as identical with G. scarburgensis. 



The specimens selected as syntypes are the two figured 

 by Morris and Lycett {loc. cit. supra) as Gervillia acuta Sow., 

 and are now in the Leckenby Collection, Sedgwick INIuseum, 

 Cambridge. They are from the Scarborough Limestone at 

 Scarborough. 



I The specific name /ancsoWd was used by Sowerby in 1826 (Min. Conch., vol. VI., p. 17, tab. 

 D.XII fig 1) for a species which he referred to Avicula [PUria], but which must, I think, be referred 

 to Gervillia. The absence of the ligament-pits from the type of " Avicula " lanceolala Sow. seems 

 to be a matter of preservation, and while there are manv similar sabre-like shells which are undoubted 

 Gervillias there is none, so far as I know, referable to Pteria. Nevertheless, Mr E. T. Newton 

 (Quart. Journ. Geol. Soc, vol. Ivii., 1901, p. 232) prefers to rctani this species m the genus Avtcula 

 [Pleria]. 



