Species of Palaeozoic Bivalved Eatomostraca, 409 



as long as high, with a flatly arched dorsal and an incurved 

 ventral border ; valves highest near anterior extremity, which is 

 bluntly pointed ; valves lowest near posterior extremity, which, 

 though imperfect in our specimens, has been decidedly more 

 acute than the anterior. 



The worn and somewhat imperfect specimen from which we 

 describe these characters gives evidence of having possessed the 

 overlapping ventral flap of the left valve common to all Bairdice, 

 The general contour of the specimen also indicates the same 

 generic affinity, although, at the same time, it cannot but be 

 remarked that this is not a typical species of the genus. 



8. Bairdia subci/lindrica, Miinster. PL XX. figs. 13 a, 13 &• 

 Cy there suhcylindrica, Miinster, Jahrb. f. Min. 1830, p. 65, no, 21, 



Length ^ inch, height ^V inch. 



A pretty, slender Bairdia, with an evenly arched dorsal border, 

 an obtuse anterior and a more acute posterior extremity, and a 

 slightly concave ventral border ; valves rounded, thickest in the 

 centre, and smooth (?). 



This resembles Bairdia gracilis of M'Coy (from the Carboni- 

 ferous Limestone), with which possibly it is identical. A similar 

 form occurs also in Permian Limestone. 



9. Cythere bilobata, Miinster. PI. XX. figs. 10 a, 10 b, 

 Cythere bilohata^ Miinster, Jahrb. f. Min. 1830, p. 65, no. 20, 



Length ~ inch, height -^ inch. 



Dorsal border highly arched, with the anterior slope shortest; 

 posterior extremity a little less blunt than the anterior ; ventral 

 border incurved; valves very convex and smooth (?). 



The only specimen of this form in the Bavarian series scarcely 

 gives so good an idea of the species as some which we have from 

 British and Belgian localities. We have examples, at least, 

 which show the ventral incurvation more decidedly than the 

 specimen figured ; and it is from this feature that Count Miinster 

 seems to have named the species. It occurs also in Russia, 



10. Cythere intermedia, Miinster. PL XX. figs. 9 a-9 e, 



Cythere intermedia, Miinster, Jahrb. f. Min. 1830, p. 65, no. 22. 

 Cythere subreniformis, Kirkby, Trans. Tyneside Nat. Field-Club, vol. iv. 

 p.l54,pl.ll.f. 23. 



Length -^ inch, height -^ inch. 



The only good-sized specimen (figs. 9 a-9 c) of this species in 

 the series is imperfect. It would appear to be the same as a 

 Permian species described by one of us as Cythere subreniformis. 

 A smaller specimen (figs. 9d, 9 e) belongs to the same species. 



Ann, §• Mag, N. Hist, Ser. 3. Vol, xv. 27 



