54 THE ENTOMOSTRACA OF 



Sub-genus — Cytherella, 1 Jones. 



Animal unknown. Carapace oblong, compressed ; smooth or pitted ; no terminal 

 denticulations : contact-margins of the right (larger) valve grooved or rabbeted on its 

 inner edge for the reception of a flange presented by the contact-margin of the left 

 (smaller) valve ; both groove and flange stronger at the posterior, than at the anterior 

 portion of the valves. 



The lucid spots (see p. 56) resemble those in Cypridina rather than those of Cy there 

 and its sub-genera. 



No. 1. Cytherella compressa, Miinster, sp. Plate V, figs. 21, 23. 



Cythere compressa, Miinster. Jahrb. f. Min., &c, 1830, p. 64 ; Neues Jahrb., &c, 1835, 



p. 445. 

 Cytherina compressa, Roemer. Neues Jahrb., &c, 1838, p. 517, t. 6, fig. 14. 



— acicxjlata, lb. Ibid., t. 6, fig. 21. [According to M. Bosquet.") 



— compressa, Reuss. Haidinger's Abhandl., iii, p. 54, t. 8, fig. 15. 



— — Bosquet. Mem. Couron. Acad. Belg., xxiv, p. 11, t. 1, fig. 1. 



? Cytherella fabacea, Bornemann. Zeitsch. Deutsch. geol. Ges., vii, p. 355, t. 20, fig. 2. 



INCH. 



Length, ^ to -^s Recent : Australia (?) ; Norway. 



Tertiary : England ; Eurojje. 



Carapace ovate-oblong or oblong ; rounded at the ends ; more or less arched on 

 the dorsal, nearly straight on the ventral border : valves smooth, sometimes faintly 

 punctate, depressed, most convex posteriorly and rather ventrally, broadest anteriorly, 

 with the anterior border sometimes raised into a slight marginal rim (fig. 23). 



Dorsal profile narrow-acute-ovate or subcuneiform ; end-view sub-ovate. 



The blue clay of Bracklesham and the London Clay of the Copenhagen Fields, 

 London, both yield this species ; which has also been found at Castell' Arqauto and at 

 Osnabriick, and in the Belgian and the Austro-Hungarian Tertiaries. 



Cytherella compressa seems to replace in the Tertiary deposits the C. ovata of the 

 Chalk, — to which it is nearly allied. 



It occurs also as a finely punctate form on the Coast of Norway (from Messrs. 

 M'Andrew and Barrett's dredgings) ; and I have a nearly related form from 

 Australia. 



1 For synonyms see ' Monog. Entom. Cret.,' 1849, p. 28 ; where further details are also given of the 

 form and character of the valves. Since the publication of the Monograph alluded to, Cytherella, like the 

 other sub-genera there established has been referred to as a genus, — and perhaps on better grounds tban in 

 the other instances. 



