412 Tate — Note on Axinopsis. 



Mr. Wetherell has also obtained, during the excavation of the London 

 clay at the Highgate tunnel for the Edgeware and Highgate rail- 

 way, a fine specimen of the Belosepion (B. sepioidea, De Blainv.) 

 similar to that figured by Mr. F. E. Edwards in his valuable mono- 

 graph on the Eocene Mollusca (Palaeont. Soc. 1849, Tab. I., fig. 1, h) 

 and found in the London clay of the Isle of Sheppey, and which now 

 forms part of the Dixon collection in the British Museum. Mr. 

 Wetherell's specimen is somewhat elliptical in form, convex, and 

 measures about 3J inches in length, by 2 inches in breadth, and 1 

 inch in depth ; it is strongly and broadly ribbed, the outer shell pre- 

 served in some places, is of moderate thickness, nearly smooth, and 

 faintly marked by lines of growth, which are crossed by finer lines 

 or strife, giving the shell a somewhat decussated appearance when 

 carefully examined. 



VI. — Note on Akinopsis gen. nov. v. Schizodus et Axinus. 

 By Ralph Tate, F.G.S. 



PEOFESSOE KING mstituted the genus Schizodus for the re- 

 ception of certain species of bivalves occurring in the Per- 

 mian and Carboniferous systems, which had previously been quoted 

 under the generic title of Axinus. In Dr. Woodward's Manual of 

 Mollusca, 2nd edit. p. 431, Axinus is retained for these shells ; and 

 Schizodus is reduced to a synonym, because the name applied by 

 Professor King had previously been employed by Mr. Waterhouse. 



The type of Sowerby's genus Axinus is A. a?igulatus, and with it 

 are associated other Tertiary species and several existmg forms. 

 Now, Axinus, as so typified and illustrated by Mr. Gwyn Jeffreys, 

 belongs to the family Lucinid(B, whilst the older shells belong to 

 TrigonidcB ; these latter can no longer be referred to Axiiius. And 

 to avoid the dual employment of this generic name I would propose 

 that of Axinopsis for the species hitherto quoted under Schizodus, and 

 incorrectly under Jixinus. 



A very common shell familiarly known as Schizodtis vel Axinus 

 cloacinus was first described by Bornemann as Tceniodon Ewaldi. 

 This generic name was adopted from Dunker, who. in 1849, de- 

 scribed and figured a Liassic shell Tceniodon eUipticus as the type and 

 unique example of a new genus. But Tceniodon, as thus proposed is 

 simply equivalent to Pleuromya, and cannot consistently be adopted 

 for the group of shells under consideration. 



I do not intend to submit a monograph on the genus, my object is 

 simply to avoid an inconvenience which is certainly experienced in 

 the preparation of lists of fossils ; but I may state that Axinopsis 

 ranges from the Carboniferous series to the true Lower Lias, is 

 widely distributed throughout Europe, and is known in the Carboni- 

 ferous and Permian strata in North America. 



The synonyms of the genus Axinopsis (Tate) would be as follows : 

 Schizodus, King (non Waterhouse). 

 Axinus, Auctores(non Sowerby, 1821). 



