Palceozoic Bivalved Entomostraca. 253 



Limestone of Charterhouse *, Somersetshire, and Woodend 

 Quarry, near Lowick^ Northumberland. 



7. Bythocypris lunata, sp. nov. 

 (PI. Vl. figs. 15 a, Ibh.) 



Lunate, highest in the centre ; dorsal border arched, ven- 

 tral border straight, except where it curves up to the extremi- 

 ties, which are subacute, and one slightly the larger ; lateral 

 contour lentiform, widest in the centre; surface smooth (?). 

 Length gij inch. 



It is only known to us from the Carboniferous Limestone of 

 Holwell, Somerset, where it was found by Mr. C. Moore. 



Bytlwcypris suhJunata^ J. & K. (Geol. Mag. 1886, p. 250, 

 pi. vii. figs. 9-11), comes near the present species in general 

 form, and is possibly nearly related to it ; but it is smaller, 

 relatively higher, and has more acute extremities. 



8. Cythere (?) gyripunctataj J. & K. 

 (PI. VI. figs. 14 a, 14 h.) 



Cythere yyriimnctata, J. & K., MS. 1885, Geol. Mag. dec. 3, vol. ii. 

 p. 640. 



Ovate in outline, highest behind, very convex ; dorsal 

 border short and straight ; ventral border convex, projecting 

 posteriorly ; extremities rounded, the anterior being smallest ; 

 lateral contour oval, with pointed extremities ; surface 

 coarsely striated and pitted concentrically ; valves apparently 

 of equal size. Length -^ to ^ inch. 



This rare species has been found only in the Carboniferous 

 Limestone of Arnside, Westmoreland. 



9. Leperditia Armstrongiana^ J, & K. 

 (PI. VII. figs. 1 a, 1 b) 



Leperditia Armstroru/iana, J. & K., MS. 1867, Trans. Geol. See. Glas- 

 gow, vol, ii. p. 2iy. 



L, Armatrongiaria is a well-marked species and can always 

 be identified by its large antero-dorsal spines, or the stumps 

 usually left of them. 



1'he valves are much higher behind than in front, with the 

 posterior extremity boldly rounded and passing imperceptibly 

 into the ventral margin, which is very convex; anterior 

 extremity much the smaller, rounded or subangular ; dorsal 

 margin straight ; lateral contour lentiform, widest a little in 

 front ot centre; surface smooth. Length yV inch. 



* Quart. Jouni. Geol. Soc. vol. xxiii. jp. 491-405. 



