JUKES-BROWNE : CRETACEOUS AND EOCENE VENERIUM. 149 



Still more recently Dr. W. H. Dall has investigated the American 

 recent and Tertiary species, and has published a synopsis of the 

 family Veneridse/ in which he has redescribed and defined all the 

 recent and fossil genera. This synopsis is unquestionably the most 

 complete account of the family which has yet been published, and 

 gives new information about some of the generic groups ; but it has 

 special reference to American species, and is not an entirely reliable 

 guide with regard to European fossils. He also makes many altera- 

 tions in the nomenclature, some of which have not gained acceptance 

 in this country. 



By British conchologists the Veneridse have certainly been much 

 neglected, for no one has published any adequate account of the recent 

 genera since the appearance of Messrs. Adams' "Genera of Recent 

 Mollusca" in 1858, nor has any critical revision of the fossil repre- 

 sentatives been attempted. 



My attention was called to the need of such revision by Mr. H. 

 Woods, who, knowing of my interest in the Veneridse, sent me some 

 of the specimens which he then had under examination for description 

 in his "Monograph of the Cretaceous Lamellibranchia." I then, for 

 the first time, realized the peculiar characters of certain Cretaceous 

 species, and perceived how greatly most of them differed from any 

 recent shells. Subsequently it became evident that it would be very 

 desirable to compare the Cretaceous and Eocene species, and I put 

 myself in communication with M. Cossmann, who was kind enough to 

 send me specimens from the Parisian Eocene to illustrate the subgeneric 

 groups which he had proposed in 1886. 



By kind permission of Dr. Teall I have had the advantage of 

 studying the excellent series of Eocene and Oligocene Yeneridse in 

 the possession of the Geological Survey at the Museum of Practical 

 Geology ; through the kindness of Mr. H. Woods I have also been 

 able to examine the fine specimens in the Sedgwick Museum at 

 Cambridge, and I have to thank Mr. Woods for other assistance and 

 for advice given during correspondence on the subject. 



The following is a list of the genera and subgenera which have been 

 recognized as occurring in the Cretaceous and Eocene deposits, or have 

 been proposed for species found therein, including some which are now 

 indicated for the first time : — 



Dosiniopsis, Conrad. dementia, Gray. 



Callista, Morch. Cyprimeria, Conrad. 



Ghionella, Cossmann. Cyclorisma, Dall. 



Aphrodina, Conrad. Fsathura, Deshayes. 



Bollfusia, Cossmann. Venerella, Cossmann. 



Tivelina, Cossmann. Mercimonia, Dall. 



Pitaria, Roemer. Chione, Megerle. 



Atopodonta, Cossmann. Textivenus, Cossmann. 



Circe, Schumacher. Veneritapes, Cossmann. 



Goiildia, Adams. Tapes, Koemer. 



Simetta, Link. Baroda, StoUczka. 



(?) Ptychomya, Agassiz. 



1 Proc. U.S. Nat. Mus., vol. xxvi (1902), pp. 335-412; see also Trans. Wagner 

 Free Inst. Sc, vol. iii, pt. 6 (1903), "Tertiary Fauna of Florida." 



