56 THE ENTOMOSTRACA OF 



London, and is well distinguished from C. covipressa by its marginal rims, central 

 impression, and ver}^ different dorsal profile, arising from the more uniform convexity 

 of the valves. 



No. 3. Cytherella Munstert, Roemer, sp. Plate V, figs. 12 a, 12 b, 13. 



Cytherixa Mcnsteri, Roemer. Neues Jahrb. f. Min., &c., 1838, p. 516, t. 6, fig. 13. 



— PARALLELA, Reuss. Verstein. Bohra. Kreid., 1 Abth., p. 16, t. 5, fig. 33; and 



Haidinger's Abhandl., iv, p. 48, t. 6, fig. 1. 

 Cythere truncata. Bosquet. Mem. Soc. Roy. Liege, iv, p. 357, t. 1, fig. 2. 



— (Cytherella) truncata, Jones. Monog. Entom. Cret., p. 30, t. 7, fig. 35. 

 Cytherella Munsteri, Bosquet. M6tn. Couron. Acad. Belg., xxiv, p. 13, t. 1, fig. 2. 



— — lb. Mem. Commiss. Carte geol. Neerl., ii, p. 58, t. 8, fig. 2. 



INCH. 



Length, ^^ Recent : Australia ; Norway. 



Tertiary : England ; Europe ; North America. 

 Cretaceous: England; Europe. 



Carapace oblong ; extremities rounded ; dorsal margin somewhat curved : valves 

 depressed anteriorly, convex posteriorly, smooth, punctate with pits in linear arrange- 

 ment, punctation sometimes strong (fig. 12), sometimes obsolete (fig. 13). [See 

 ' Monog. Entom. Cret.,' p. 30, for fuller details.] 



The lucid spots are numerous, small, and closely packed together ; they occupy 

 a sub-triangular space near the centre of the valve and rather ventrally, and are 

 arranged in two parallel, slightly curved rows, the largest spots at the ventral end and 

 the smaller ones gradually tapering upwards, so that the spots form a short broad 

 feather-like patch. 



Dorsal aspect elongate wedge-shaped ; end-view sub-oval. 

 Cyiherella Munsteri is very closely related to C. compressa and C. ovata. 

 Specimens of C. Munsteri occur at Colwell, Barton, Bracklesham, and in the 

 London Clay of Copenhagen Fields and of Wimbledon Common, near London. 



This species is also found in the Tertiary and the Cretaceous beds of Belgium 

 and the Netherlands ; the Cretaceous beds of Bohemia, Gallicia, and Sweden ; and in 

 the White Chalk, Chalk-marl, and Gault of England. I have also found it in a 

 Tertiary sand from Alabama. Coarsely punctate valves of C. Munsteri occur in the 

 dredged sand from the Norway Coast, with which Messrs. M'Andrew and Barrett 

 have favoured me ; and I have a delicate smooth variety from Australia (where also a 

 Cytherella of the G. W'lliamsoniana type occurs recent). 



