16 CARBONIFEROUS ENTOMOSTRACA. 



viduals (figs. 19, &c.). A gape of moderate proportions (indicated in the outlines, figs. 

 16 5 and 19 ^) accompanies this deep sinus. Some valves (fig. 18) have a slight 

 marginal rim on the ventral edge. End-view obovate ; edge view compressed ovate, and 

 nearly oblong-oval in the fine old specimen, fig. 19 c, which has its surface somewhat 

 depressed across the middle. 



In the males of Philomedes interpunda (Baird), and in Cypridina Reynaudi, 

 M.-Edwards, and C. Bairdii, Brady, the antero-ventral region of the carapace slopes away 

 rapidly backwards, as in C. hrevimentum ; but there are no other mutual characters of 

 similarity. 



This species, gregarious hke many other Cypridinads, is evidently of common occur- 

 rence in the Mountain-limestone of Ireland^ England, and Belgium. Taken according 

 to gradations in shape — 



Fig. 16 (the smallest) is a grey shell in grey limestone from Cork (Mr. Joseph Wright, 

 F.G.S.). It is a fifth too large to be M'Coy's Daphnia prwmva, and differs from it 

 essentially in shape. We have a similar specimen from Vise (Belgium), thanks to our 

 friend M. J. Bosquet, F.C.G.S. of Maestricht. 



Fig. 15 is a grey shell, roughened by partial solution and weathering, and cracked (as 

 shown in the figure), in grey hmestone from Little Island, Cork ; Mr. Joseph Wright, 

 F.G.S. 



Fig. 18 is a whitish weathered shell in grey Mountain-limestone from Parkhill, near 

 Longnor, Derbyshire, associated with a small Aviculopeden and small bivalves. The 

 specimen is in the Museum of the Geological Survey, Jermyn Street (Tablet ff), where 

 there are two others similar, one a cast and one with a film of shell remaining (fig. 19), 

 from the same place. 



Fig. 17 is a grey shell in the grey limestone of Cork, collected by Mr. Joseph 

 Wright, F.G.S. This species is plentiful at Little Island. 



Fig. 19 (the largest) is a black cast, retaining some straggling films and broken reti- 

 culations of shell-matter, in dark grey encrinital limestone, in which the constituent 

 fossils are partially darkened with bitumen, from Parkhill, Longnor, Derbyshire. It is on 

 Tablet ff in the Museum of the Geological Survey, London. [The beak over the notch 

 is rather sharper in the specimen than in the figure.] 



Fig. 16 length 



1 . 



5 J 



height 



thickness 



inch. 



Proportions 9 



: 51 



4. 



Fig. 17 „ 



2 . 



7 ' 



i . 



jj 6 ' 





? 



J5 





4. 





Fig. 15 „ 



1 . 



3 ' 



1 . 



>> 5 J 



J> 



1 



7 



JJ 



8 



^2 



02 



Fig. 18 „ 



1 . 



3 ' 



5 . 



JJ 2 4' 



J5 



1 



6 



» 



73 

 ' 4 



5 : 



4. 



Fig. 19 „ 



5 . 



1 2 5 



i . 



J> 



1 

 6 





10 : 



6 : 



41 



In the Carboniferous Limestone of Caldy Island, South Wales, the late Mr. J. 

 W. Salter observed a gregarious Cypridinad, either of this species or possibly Polycope 

 simplex. 



