242 PROCEEDINGS COTTESWOLD CLUB 191 1 



GERVILLIA CORINIENSIS sp. nov. PL xxix., figs. la & b. 



T.l. Quarry one mile W.S.W. of Siddington St. Peter, near Ciren- 

 cester, Gloucestershire. 

 H. Forest Marble. Bathonian. 

 Colin. L. Richardson. 



Description (left valve). — A Gervillia characterized by seven transverse 

 costae. The shell is elongate, tapers posteriorly, and hcis a concave postero- 

 dorsal margin. The cardinal margin is produced posteriorly and is approxi- 

 mately -6 of the length of the shell. 



The hinge-area is large for the size of the shell and is traversed by three 

 oblong ligamentary sulcations. The test is thick. 



Measurements. — Length, 78 mm. ; height, about 33 mm. ; length of 

 the hinge margin, ?46 mm. 



Remarks. — This species differs from Gervillia crassicosta 

 Morris and Lycett, in having fewer ribs, no secondary ribbing, 

 and in being more elongate. 



GERVILLIA CRASSA James Buckman {ex Strickland MS.) 

 PI. xxviiL, figs. la, b, c, and d. 



T.d. 1844. " An Outline of the Geology of Cheltenham," 2nd ed., 



Appendix, p. 98. 

 T.f. Ibid., tab. 10, fig. g. 

 T.l. " Railway-cutting in several places between Gloucester and 



Bredon." 



H. " Lias." [? Top of Sinemurian] 



y). [? obtusi-stellaris] 



Colin. Mus. Pract. Geol., Jermyn Street, London. [3684]. 



Type-description. — " Hinge-line a little more than half the length of the 

 shell, teeth few, shell thick, very rugose. 



Remarks. — The species differs from Gervillia Icevis in being 

 proportionately higher, in having a more sinuous antero-ventral 

 margin and a more concave postero-dorsal margin, and in being 

 more rounded at the posterior extremity. 



Gervillia hagenowii Dunker' resembles this species. It may 

 be distinguished therefrom by the antero-ventral margin, which, 

 in G. hagenowii descends from the umbo for about half the 

 length of the shell at an angle of approximately 50° with the 

 hinge-line. In G. crassa, the antero-ventral margin makes an 

 angle of from 60° to 70° with the hinge-Une. This gives G. crassa 

 a more quadrate appearance, and makes its anterior end less 

 acuminate than in G. hagenowii. 



I Ueber die in dein Lias bei Halberstadt vorkoinineiiden Versteinerungen (1851), pp. 37-38, 

 tab. vi., figs. y-ii. 



