86 R. BULLEN NEWTON on 



from the Brockenhurst Beds (Headon-Hill Series) of Hampshire belonging to 

 the Lower Oligocene (Tongrian). Specimens from the British Barton and 

 Bracklesham Beds, with sub-trigonal and well inflated valves, have long lain 

 in the Edwards Collection at the British Museum under the manuscript name 

 of Meretrix bartonensis ; these it is now considered should be regarded as 

 C. incrassata. 



This species forms the type of M. Cossmann's sub-genus Cordiopsis, 

 established in 1910, which appears to be closely related to Sinodia of Jukes- 

 Browne, 1908, founded on Reeve's recent shell, Dosinia trigona. Without 

 discussing the points of difference raised by the two authors it may be 

 mentioned that Sinodia was grouped by Jukes-Browne with Dosinia, while 

 Cordiopsis is regarded by M. Cossmann under Meretrix, the views of the 

 latter being, however, adopted on this occasion more especially as Sowerby's 

 V. incrassata has so commonly been associated in the past with the genus 

 Meretrix ( = Cytherea), whilst the new species of Sinodia from Southern 

 Nigeria would favour a like result. 



DISTRIBUTION. British : Middle (Lutetian) and Upper (Bartonian) Eocene, 

 Lower Oligocene (Tongrian). (Headon and Bembridge Series). Europe: 

 Oligocene (Tongrian) ; Miocene (Aquitanian). Egypt : Upper Mokattam 

 (Bartonian) ; related forms. 



OCCURRENCE. Cuttings Nos. 5, 6, 10, 12, 15. 

 COLLECTOR. Mr. Kitson. 



Sinodia heward-belli, sp. nov. 

 PLATE 9, figs. 18-21. 



DESCRIPTION. Shell ovately trigonal, inaequilateral, height in excess of 

 length, thick, ventricose ; dorso-anterior margin straight, oblique, posterior 

 margin long, compressed and nearly vertical in the centre, ventral margin 

 rounded ; umbones acute, laterally approximate, strongly anterior (prosogyrous) ; 

 lunule widely cordiform, well circumscribed, not impressed ; ligament groove 

 narrowly elongate, situated within a shallow escutcheon area margined by an 

 obtuse angulation which is succeeded by a distant and more obscure angu- 

 lation ; pallial inflection broadly lingulate, antero-laterally ascending, obtusely 



