16 
THE ENTOMOSTRACA OF 
No. 1. Cytherets interrupta, Bosquet. Tab. II, fig. 6 a — h. 
Cypridina interrupta, Bosquet. 1847. Entom, foss. Maestricht, p. 12, n, 3, pi. ii, fig. 1. a — d. 
Var. a and j3. 
INCH. 
INCH. 
Length, 
1 
4TT 
1 
Height, 
1 
8S' 
1 
6 0 
Thickness, 
1 
85 
Greensand, Blackdown. 
Detritus, Charing. 
Chalk, Woolwich. 
Var. a. Gault, Leacon Hill and Folkstone. 
Var. /3. Gault, Folkstone. 
Var. y. Greensand, Farringdon. 
Chalk, Maestricht {Bosquet), Upper Oolite, Dorsetshire. 
Carapace oblong. Valves convex, slightly depressed towards the dorsal border, 
usually pitted like the surface of a thimble ; punctation subconcentric. Anterior 
extremity depressed, rounded, slightly bearded ; posterior narrower, subacute ; both 
extremities having a slight marginal ridge. Superior and inferior margins nearly 
straight ; a slight ridge sometimes present near the ventral border. Hinges very 
slightly developed. The central and the two posterior tubercles nearly obsolete. 
Dorsal dnd ventral aspects somewhat oblong ; anterior extremity narrower than the 
posterior, strongly produced ; posterior slightly produced. Anterior aspect somewhat oval. 
This species occurs in the Charing Detritus ; it is very rare in the Chalk and the 
Greensand. M. Bosquet describes it as occurring at Maestricht. It is found also 
in the Upper Oolite (white limestone with flints) at Upway, Dorsetshire. 
Variety a, figs. 6(5, 6/. 
Gault, Leacon Hill, near Charing, and Folkstone. 
In this variety the height of the valves is proportionally greater. The anterior 
and posterior margins are bearded ; the anterior marginal ridge is strongly marked ; 
the whole surface of the valves is bristled with fine spines ; and the punctations are 
confined to the middle of the valves. Central tubercle is obsolete. The posterior 
tubercles are sometimes slightly acuminate. Near the centre of the valve in this 
and the following variety is observable (by transmitted light) a patch of 4-5 oval lucid 
spots arranged in two little groups, 3-4 small spots in the one, and 1-2 larger spots 
in the other group. Plentiful at Leacon Hill, near Charing, Kent. 
Variety (3, figs. 6c, 6d, 6g. 
Gault, Folkstone. 
Similar in size and shape to var. a ; the valves are setaceous ; central tubercle 
sometimes covered with closely set, short, strong spines. Punctations more or less 
obsolete. This variety is very plentiful in the Folkstone Gault. 
