218 Prof. T. R. Jones and Dr. H. B. Holl on 



the surface of the valves is seen in Cythere [/EchminaT] umbo- 

 nata 7 Williamson, from the Chalk (Monograph Cretac. Entom. 

 Pal. Soc. 1848, pi. 2. fig. 3), in which the sharp boss is some- 

 what variable in its position, though mainly affecting the 

 postero-ventral region. 



1. JEchnina cuspidata, n. sp. PI. XIV. fig. 8, and woodcut, 



fig. 2. 



Carapace-valve suboblong, 

 convex and produced at the 

 middle (towards the postero- 

 dorsal region) into a stout 

 sharp spike ; dorsal edge 

 straight, ventral edge ellipti- Fig. 2. JI£ehmina cuspidata. 



cal ; one end more broadly Right valve : the spine is broken, 

 rounded than the other. (Magnified about 20 diameters.) 



We have here evidently a very close approximation to Pro- 

 fessor James Hall's Cytherina {JEchmina\ spinosa (Palseont. 

 New York, vol. ii. p. 317, pi. 67. figs. 17-21), from the Niagara 

 Shale at Lockport, in the State of New York ; but the latter 

 is more quadrate in outline and somewhat depressed at the root 

 of the spine, which, though nearly central, is near the dorsal 

 margin. 



The fragment figured obliquely in PI. XIV. fig. 8, and 

 more definitely shown in the woodcut, fig. 2, is from the Wen- 

 lock Limestone of Croft's Quarry, near West Malvern. 



2. JEchmina clavulus, sp. nov. Woodcut, fig. 3. 



This is smaller and relatively 

 shorter than the foregoing, and 

 has nearly all the surface of the 

 valve taken up with the root of 

 the great spike or spine, which 

 is proportionally larger than that 

 in 2E. cuspidata. \ / 



Found in the Wenlock Lime- / /' 



stone, with the last men- p- lg . 3. JEchmina davulus. 

 tioned. Both valves, one of them restored. 



(Magnified about 20 diameters.) 



BeyricJiia intermedia, sp. nov. PI. XV. fig. 7. 



Carapace-valve small, convex, suborbicular (length to height 

 as 4 to 3|) ; ventral edge semicircular, ends boldly curved, 

 one rather less so than the other ; dorsal edge indicated by the 

 straight portion of the margin and by two short unequal fur- 

 rows widening out from near the central surface of the valve 



