78 



CARBONIFEROUS ENTOMOSTRACA, 



PI. VII, fig. 12, but its posterior border is more neatly semicircular, and the proportional 

 convexity and compression, as seen in the profile, are not exactly matched in the 

 above-mentioned figures. We look on it as a local and large representative of the same 

 species. 



Length ri6; height '12; thickness '56 mm. Proportions 29 : 18 : 14. 

 It is from the Upper Coal-measures of Iowa, United States of America, and is in 

 Mr. D. Robertson's collection. 



19. Cytherella Benniei, var. intermedia. Nov. Plate VII, figs. 7 a, b. 



This subelliptical carapace is simple in outline, and smooth, like many other Cytherellce, 

 and without any very distinctive characters. It comes near C. Benniei, though rather 

 weak posteriorly — that is, narrower and more compressed behind than most of its Scotch 

 congeners, and more so also than var. lowensis. Smaller than the last mentioned, it is 

 about as long (though not nearly so stout) as the individuals from Kennoway Den, Pife 

 (PI. VI, fig. 7). We will call it var. intermedia. 



Length 1*0; height -56; thickness "4 mm. Proportions 25 : 14 : 10. 



It is in Mr. D. Robertson's collection, and was got from the Upper Coal-measures of 

 Iowa, U.S.A. 



20. Cytherella regularis. Sp. nov. Plate VII, figs. 6 a, h. 



Carapace elhptical in outUne ; narrow-oval in profile ; almost symmetrical in the 

 curves of both dimensions. Smooth ; muscle-spot distinct, though faint. 

 Length *76 ; height '48 ; thickness "32 mm. Proportions 19 : 12 : 8. 

 From the Fusulina-limestone of Iowa. In Mr. John Young's collection. 



21. Cytherella regularis, var. ? Plate VII, fig. 9. 



This symmetrically ovate carapace-valve, with relatively slight convexity, is from the 

 Carboniferous Formation at Danville, Illinois, U.S.A., and was communicated by Professor 

 McChesney. It may be a small variety of C. regularis, above described, from Iowa. 



Length -52 ; height -32; thickness ? mm. Proportions 18 : 8 : ?. 



