CYPRIMERIA. 185 



Non 1840. Venus parva, A. Qoldfuss. Petref. Germ., vol. ii, p. 246, pi. cli, fig. 4 



( V. Goldfussi, Geiuitz, 1 850 ; V. subparva, 

 d'Orbigny, 1850). 

 1841. — F. A. Bomer. Die Verstein. d. nord-deutsch. Kreidegeb., 



p. 72 (Venus subinflexa, Romer, 1836). 



— 1846. A. E. Reuse. Die Verstein. der bohm. Kreideformat., pt. 2, 



p. 20, pi. xli, figs. 16, 17. 

 1863. — A. v. Strombech. Zeitschr. der deutsch. geol. Gesellsch., 



vol. xv, p. 146. 

 1868. A. Briart and F. L Cot-net. Meule de Bracquegnies (Mem. 



cour. et Mem. ties Sav. etrangers, 

 vol. xxxiv), p. 75, pi. viii, figs. 1, 2. 



— 1877. Cytherea parva, O. Bohm. Zeitschr. der deutseh. geol. Gesellsch., vol. xxix, 



p. 241. 

 1883. Venus cf. parva, A. Fritsch. Stud, im Gebiete der bohm. Kreideformat., iii, 



Iserschicht., p. 109, fig. 77. 

 1885. Venus parva, F. Notlinq. Die Fauna d. baltisch. Cenoman. (Palaeont. 



Abhandl., vol. ii), p. 32, pi. v, fig. 11. 

 1893. Fritsch. Op. tit., v, Priesen. Schicht., p. 98, fig. 118. 



Description. — Shell small, oval, convex, moderately inequilateral. Antero- 

 dorsal margin slightly concave, or nearly straight, forming a rounded angle with 

 the anterior margin which curves rapidly to join the convex ventral margin. 

 Posterior margin rounded or subtruncate. Postero-dorsal margin slightly convex. 

 Umbones rather prominent, curved inwards and forwards. Lunule broad, ovate, 

 more or less projecting, limited by a groove. Pallial sinus large, angular. 

 Ornamentation consists of small, somewhat irregular, concentric ribs, and occasional 

 growth-rings. 



Hinge : In the right valve the anterior and median cardinals are stout and 

 nearly parallel, and the two posterior teeth (which represent the posterior cardinal) 

 are oblique and diverging ; in front of the anterior cardinal is a groove, bounded 

 by a ridge above and below, parallel to the inner margin of the hinge-plate. In 

 the left valve the anterior and median cardinal teeth diverge widely under the 

 umbo and the posterior cardinal is oblique; the anterior cardinal is continued 

 forward into a ridge along the inner margin of the hinge-plate. 



Measurements .• 



(1) (2) (3) (4) (5) 



Length . 20-5. 21 . 20 . 20 . 19 

 Height . 17 . 17-5. 17-5. 17 . 10 



(1) Perna-bedL, East Shalford. 

 (2—8) Crackers, Atherfield. 

 Affinities. — The differences between this species and G. (Gyclorisma) rotomagensis 

 are given below. 



The form from Bracquegnies, which was referred to Venus parva by Briart and 

 Cornet, is less elongate. 



(6) 



m 



(8) 



16 



. 14 . 



1 mm . 



14 . 



12 . 



8-5 „ 



