MACROCYPRIS SILTQUA. 9 



These features are represented more or less closely in our Bairdia Harrisiana, 

 but on a smaller scale. Of course these may be sexual differences, but it is 

 unsafe to hazard an opinion on this point. 



Locality. — Two valves from the Chalk of Kent. 



ly. Macrootpeis, Brady, 1867. 

 In this genus the right valve is larger than the left. 



§ I. Species belonging to the same group as M. Minna (Baird) and others of like 

 form. Several of these elongate species have been described and figured, 

 especially by Dr. G. S. Brady in his 'Challenger Eeport,' 1880, p. 41, 

 &c., and pi. ii. 



1. Macroctpris siliqua, Jones. Plate II, figs. 38 — 41. 



Baiedia siIiIQUA, Jones. Monogr. Entom. Cret., 1819, p. 25, pi. v, figa. 16 a — d 



(not figs. 16 e,f, g, h). 

 Maoeoctpeis siliqtja, Jones. Geol. Mag., 1870, pp. 75, 77. 



Fig. 41, right valve, inside. Length 1*41 ; height "5 mm. 



Fig. 40, right valve, outside. „ 1*27; „ -47 „ 



Fig. 39. Thickness "25 mm. 



Fig. 38. Length 1*16 ; thickness '3 mm. 



This well-developed Macrocypris has many relatives in the recent state, but 

 none of exactly the same form. The valves are long, subtriangular, narrow, 

 convex, smooth ;^ strongly arched on the back, slanting off posteriorly ; ventral 

 margin nearly straight ; contracted and rounded in front,^ acuminate behind. 



Localities. — From the Glialk,^ Bally tober (Antrim), Keady Hill (Derry), and 

 South-eastern England; the Detritus, Charing; and Greensand, Ventnor, Isle 

 of Wight. 



Foreign. — Eocene, Clausenberg, Transylvania (A. von Pavay). 



^ Not spined or prickly as in fig. 16 c. 



2 The anterior curvature baa been made ratber too flat and broad in the reproduction, fig. 41. 

 ' In this, and in all the other cases of Irish Chalk, the powder from the flints is referred to ; 

 and there are other localities besides those specially mentioned (see above, page 2). 



