408 Messrs. T. R. Jones and J, W. Kirkby on Munster's 



5. Cytherella^{l) inflata, Miinster, sp. PI. XX. figs. 8 a-S c, 

 Cy there inflata, Miinster; Jahrb. f. Min. 1830, p. 65, no. 17. 



Length -Jj- inch, height Vo- inch. 



A swollen, nearly ovate form, with the dorsal border faintly 

 convex and the free margin elliptical. The anterior extremity 

 is somewhat more acute than the posterior. The valves are 

 thick, very gibbous ventrally and rather anteriorly, sloping 

 gradually to the dorsal border and backwards, but pinched up 

 suddenly anteriorly ; they are also margined along their free 

 edges with a slightly lipped rim, and have a faint circular hum- 

 mock in a shallow hollow in their centre. 



The same form occurs in the Carboniferous Limestone of Vise, 

 in Belgium, and in the Carboniferous (marine) shales of Craigen- 

 glen, Campsie, Scotland. It is evidently not a Cy there, but 

 approaches more nearly to Cytherellaj in which genus we have 

 placed it. 



The foregoing are figured in PL XX. with the dorsal margin 

 upwards ; the following [Bairdice and Cythera) are figured with 

 the anterior end upwards. 



6. Bairdiaf Hisingeri, Miinster. PI. XX. fig. 12 a-12 c, 



Cythere Hisingeri, Miinster, Jahrb. f. Min. 1830, p. 65, no. 18. 



Bairdia Schaurothiana, Kirkby, Ann. Nat. Hist. ser. 3. vol. ii. p. 329, 



pi. 10. fig. 14, 1858; and Trans. Tyneside Nat. Field-Club, vol. iv. 1859, 



p. 147, pi. 9. fig. 14, and woodcut 10. 



Length -jV inch, height -o-y inch. 



A good Bairdia, with a straight, abruptly sloping posterior 

 extremity, an arched dorsal margin, a slightly convex inwardly 

 sloping anterior extremity, and a nearly straight ventral margin; 

 the valves swell most in the centre, and slope away to rather 

 trenchant edges at each extremity. 



The single example of this species among Herr Giimbe?s Ba- 

 varian specimens enables us to identify it with Bairdia Schauro- 

 thiana, Kirkby, of the Permian strata of Durham. Bairdice the 

 same as this occur also in the Carboniferous strata of Britain. 



7. Bairdia elongata, Miinster. PL XX. figs. 14«-]4c. 



Cythere elongata, Miinster, Jahrb. f. Min. 1830, p. 65, no. 19, 



Length ^ inch, height —^ inch. 



A curious elongate subcylindrical form, more than three times 



* As one of us has already indicated (Monogr. Tert. Entom. pp. 9 & 54), 

 there is no doubt of Cytherella being generically distinct from Cythere, and 

 probably a member of a different family — namely, of the CypridinidcB. 



t Bairdia is not yet proved to be generically distinct from Cythere; but 

 it is convenient to use the term independently. 



