32 THE ENTOMOSTRACA OF 



Dorsal asj^ect elongate-subovate. 



This species closely resembles C. scabra, Miinster, figured and described by Bosquet, 

 ' Descrip. Entom. Tert.,' p. 103, t. 5, fig. 7 ; but, instead of smooth tubercles, the latter 

 has ragged lamellar tubercles. Such exogenous growths as tubercles and spines are 

 subject to great variations of development, and must be used with caution for specific 

 characters ; still I prefer to regard tlie form under notice as distinct from C. scabra. 



Cytliere scabropapulosa occurs at Bracklesham, and is rare. C. scabra, accordmg to 

 Bosquet, belongs to the Subapennine deposits of tlie South of France, and the Miocene 

 beds of Dax ; Roemer derived it from the North-west of Germany (Osnabruck), and 

 from Bordeaux. 



No. 15. Cythere costellata, Hoemer, sjj. Plate V, fig. 11. 



CvTEERiNA COSTELLATA, Roemer. Neues Jalirb. f. Jlin., &c., 18.38, p. 517, t. 6, fig. 24. 

 Cythere costellata. Bosquet. Mem. Couvon. Acad. Belg., sxiv, p. 58, t. 2, fig. 11. 



IXCH. 



Length, Vj- Middle EoceDe : Eugland and France. 



Carajjace ovato-oblong ; rounded before, narrow behind ; dorsal border straight, 

 ventral slightly convex : valves most convex posterior to the centre, depressed ante- 

 riorly ; front and hind margins more or less denticulate ; surface covered by several 

 narrow, rounded, longitudinal, slightly sinuous ribs, placed side by side (10 or 1 1 in ray 

 specimens, 7 or 8 in M. Bosquet's, and "about six" in M. Roemer's). 



Dorsal aspect elongate-acute- ovate; end-vieio ovate. 



A slight difference in the number of the superficial riblets exists amongst the 

 specimens figured and described, — as above noticed ; and there also appears to be a 

 somewhat greater convexity in Roemer's 6-ribbed form than in Bosquet's 7- or 8- 

 ribbed specimens, and in the latter than in my 10-ribbed specimens. 



Bosquet enumerates several localities for C. costellata in the " Sables moyens," the 

 " Calcaire grossier," and in the " Sables inferieurs " of France. Roemer's specimens 

 also came from the Paris Tertiaries. In England I have only met wdth this species in 

 the sandy blue clay at Bracklesham, where a single specimen (perfect carapace) was 

 obtained. 



No. 16. Cythere plicata, Miinster. Plate IV, fig. 16 ; PI. V, figs. 8 «— 8 d; 



PI. V, fig. 17. 



