VOL. XVII. (2) JURASSIC GERVILLLE 241 



GERVILLIA BICOSTATA Lycett. 



Td.. 1863. Suppl. Monogr. Moll. Gt. Ool., pp. 111-112. Pal. Soc. 



T.f. Ibid., tab. XL., fig. 21. 



T.l. " Bussage, near Bisley [near Stroud]." 



H. " Great Oolite." [Bathonian] 



[" maxillata; ."'I 

 Colin. 



Record. — The holotype appears to be unique. 



GERVILLIA COMPRESSA Whidborne. PI. xxix., Fig. 5 



T.d. 1883. Quart. Journ. Geol. Soc, vol. xxxix., p. 517. 



T.f. Ibid., pi. xvi., fig. 6. 



T.l. " Nailsw^orth, Gloucestershire." 



H. " Inferior Oolite." [Aalenian] 



^]. [bradfordensis] 



Colin. Mus. Pract. Geol., Jermyn Street. [8863]. 



Remarks. — The holotype of Gervillia compressa is labelled 

 " Gervillia lata Phill. I.O. Nailsworth." Probably this was 

 Lycett's identification of the species. The matrix is a white 

 oolitic freestone and is evidence that the specimen was obtained 

 from either the Bradfordensis-Beds or the Lower Freestone at 

 Nailsworth — probably from the old Scar Hill Quarry. 



Compared with Gervillia lata Phillips, this species is more 

 elongate, and has a relatively shorter hinge-line. G. lata, 

 moreover, does not possess the marked, slightly concave carina, 

 extending from the umbo to the posterior extremity of the 

 shell ; nor is it so flattened along the antero-ventral border. 



The statement in Whidborne's description that the hinge- 

 line of G. compressa is " nearly of the same length as the shell " 

 is inaccurate, even when it is remembered that the so-called 

 " -length of the shell " in his description is what is now called the 

 " height." The following measurements have been taken from 

 the holotype. Length (measured parallel to the hinge-line), 

 67 mm. ; height (measured at right angles to the hinge-line), 

 37 mm. ; length of the hinge-margin, 48 mm. 



Record. — Bradfordensis-Beds or Lower Freestone, Nailsworth, Gloucester- 

 shire. 



