SUPER-ORDER III 



OSTRACODA 



847 



transverse or longitudinal lines. Oi-lo\ i, i,,n to Carboniferous; very profuse in 

 Devonian. 



Entomidella, Jones. Likr 

 Entomis, but with furrow extending 

 entirely across the valves to ventral 

 edge. Cambrian to Silurian. 



Elpe, Barr. Shell ivnil<.rm, 

 3 nun. to 7 mm. long, with depres- 

 sion just behind the middle of dorsal 

 slope ; posterior half sometimes 

 strongly inflated. Delicate radial 

 ornament. Ordovician and Silurian. 



Fio. 1351. 



Family 8. Cypridinidae. Sars. 



Fio. 1350. 



I pelagica, Barr. 

 Lower Devonian (F); 

 Konieprus, Bohemia. 



/;///<, /in'.-- ."i-nito-iitriata, Sandb. 

 sp. Upper Devonian ; WeilhurK, 

 Nassau. A, Fragment of matrix, 

 Vl. B, \Vntral and lateral aspect*, 

 B /I. C, Impression of valve, >/i. 



Shells equivalve, sub-elliptical to 

 oblong, convex, smooth or punctate, 

 and sometimes ribbed, especially in posterior half. Anterior end with a notch and hook- 

 like hood overhanging an opening left between edges of valves for protrusion of the lower 

 antennae ; posterior extremity frequently acuminate. 



Cypridina, Milne-Ed\v. (Fig. 1352). Shell generally acuminate, oviform, rarely 

 oblong ; antero-dorsal edge projecting beak-like over the strongly defined notch ; 

 muscle spot large, sub-central, often visible on exterior. Ordovician to Recent 



Cypridinella, J. K. and B. Like Cypridina, but having the antero-ventral region 

 projecting somewhat prow-like and generally beyond the hook. Carboniferous. 



Fio. 1352. 



Cypridina primaeva, de Kon. 

 sp. Coal Measures ; Braid- 

 wood, England. 4 /i (after J. 

 K. and B.). 



Fio. 1353. 



Cypridella Wrigktii, J. K. B. Carbon- 

 iferous Limestone ; Cork, Ireland. 8/, (after 

 J. K. and B.). 



Fio. l.v,;. 



CypreUa chrysalidea, de 

 Kon. Carboniferous 

 Limestone ; Cork, Ire- 

 land. /! (after J. K. 

 and B.). 



Cypridellina, J. K. and B. Differs from the last in having a tubercle or lump 

 above the centre of the valve. Carboniferous. 



Cypridella, de Kon. (Fig. 1353). Like Cypridellina except that it has a curved 

 sulcus behind the tubercle. Carboniferous. 



CypreUa, de Kon. (Fig. 1354). Shell much as in the last, but annulate. Carboni- 

 ferous. 



Sulcuna, Rhombina, J. K. and B. ; Cyprosis, Cyprosina, Jones. Palaeozoic. 



Family 9. Entomoconchidae. 



Shell sub-globose, more or less inequivalve ; front edge truncate and icith central 

 portion of margin inturned so as to leave a simple or sinuate slit. Beak not developed. 



Entomoconchus, M'Coy ; Offa, Jones, Kirkby and Brady. Carboniferous. 



Geological Range of the Ostracoda. 



Undoubted Ostracoda are first met with in the Upper Cambrian, and certain 

 problematical remains indicate that they were initiated even earlier. Their post- 



