30 



CARBONIFEROUS ENTOMOSTRACA. 



6. Cypridella cyprelloides. Sp. iiov, Plate IV, figs, t) a — c. 



Carapace-valve acute-ovate ; pointed behind ; indented in front with a shallow open 

 sinus, leaving a blunt beak and retreating breast. Large, long, prominent tubercle, 

 placed forwards and pointing backwards ; and a strong sulcus behind it. Edge-view of 

 carapace acute-irregular- oval ; end-view rhombic. 



This much resembles Cyprella chrysalidea, De Koii., in form ; but it is quite smooth, 

 having no annulation. It may be regarded either as a link or an isomorph. It is a 

 light-grey shell from the Carboniferous Limestone of Cork, Ireland. Collected by Mr. J. 

 Wright, F.G.S. 



Length \; height ^ ; thickness \ inch. Proportions 8:5:5. 



V. SULCUNA. Gen.nov. 



The carapace-valves are much like those of Cypridella Wriyhiii (PI. IV, fig. 1) in 

 lateral outline, being ovate-oblong, elliptical behind, and truncate and more or less 

 indented, with sinus and notch, in front ; but the nuchal sulcus is much more definitely 

 and deeply marked. It passes obhquely downwards and forwards, undercutting 

 the antero-dorsal region, and raising it into a slanting hump or even a backward-pointing 

 process. 



There is a tendency to point backwards in the subcentral tubercle of some Cyjjridella ; 

 and were the high position of the tubercle (as in PI. IV, fig. 1) accompanied by a 

 more backward development than even in Fig. 9, and associated with a strong and 

 oblique furrow under the tubercle, we should have the main characters of our new 

 genus. 



1. SuLCUNA LEPUs. Sp. nov. Plate IV, figs. Q> a, b ; la, b, c. 



Valves ovate-oblong, truncate in front, rounded behind ; antero-dorsal region formed 

 into an oblique hump by the slanting nuchal furrow. Front margin indented ; the sinus 

 appears shallow in fig. 7 a, but deeper in fig. 6 a. The end-view of the carapace would 

 present an acute-oval outline, with two suboval projections above. 



Fig. 6. Length ^ ; height ^ ; thickness Proportions 8:5 : 3. 



Fig. 7. „ i; „ „ 1 „ 12:8:5. 



Rare in the Carboniferous Limestone of Little Island, Cork. Mr. Joseph 

 Wright, F.G.S. 



