SUBCLASS II 



EUCRUSTACEA—OSTRACODA 



741 



Family 7. Entomidae Jones. 



Shells relatively short, strongly convex, reniform, ovate or rounded quadrate, suh- 

 equivalve, luith a more or less loell-marked depression near the middle of dorsal region. 

 Surface sculpture concentric or radiate. 



Entomis Jones (Figs. 1432, 1433). 

 slightly curved sub-naedian vertical 

 furrow extending to the hinge line ; 

 in front of furrow occasionally a 

 rounded tubercle. Surface marked 

 generally with raised, concentric, 

 transverse or longitudinal lines. 

 Ordovician to Carboniferous ; very 

 profuse in Devonian. 



Entomidella Jones. Like En- 

 tomis, but with furrow extending 

 entirely across the valves to ventral 

 edge. Ordovician and Silurian. 



Elpe Barr. Shell reniform, 3 

 mm. to 7 mm. long, with depres- 

 sion just behind the middle of the 

 dorsal slope ; posterior half sometimes strongly inflated 

 Ordovician and Silurian. 



Shell sub-ovate or fabiform ; valves with a 



A B 



Fio. 1432. 



Entomis pelagica Barr. 

 Lower Devonian (F) ; 

 Konieprus, Bohemia. 



Fig. 1433. 



Entomis serrato-striuta (Sandb.). 

 Upper Devonian ; Weilburg, 

 Nassau. A, Fragment of matrix, 

 Vi- B, Ventral and lateral aspects, 

 s/j. C, Impression of valve, 9/i. 



Delicate radial ornament. 



Family 8. Cypridinidae Sars. 



Shells equivalve sub-elliptical to ohlong, convex, smooth or punctate, and sometimes 

 ribbed, especially in posterior half. Anterior end ivith a notch and hook-like hood over- 

 Tianging an opening left between edges of valves for protrusion of the lower antennae ; 

 posterior extremity freqxhently acuminate. 



Gypridina Milne Edw. (Fig. 1434). Shell generally acuminate, oviform, rarely 



Fig. 1434. 



Cypridina primaeva (de 

 Kon.). Coal Measures ; Braid- 

 wood, England. •>/, (after 

 Jones, Kirkby and Brady). 



Fm. 1435. 



Cypridella v.yrightii J. K. and B. Lower 

 Carbonifennis ;( Corlv, Ireland. ^/i (after 

 Jones, Kirkby and Brady). 



Fig. 1436. 



Cyprella chrysalidea (de 

 Kon.). Lower Carboni- 

 ferous ; Cork, Ireland. 

 *li (after Jones, Kirkby 

 and Brady). 



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

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



Gypridinella J. K. and B. Like Gypridina, but having the antero-ventral region 

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



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

 above the centre of the valve. Carboniferous. 



Gypridella de Kon. (Fig. 1435). Like Gypridellina, except that it has a curved 

 sulcus behind the tubercle. Carboniferous. 



Gyprella de Koninck (Fig. 1436). Shell much as in the last, but annulate. 

 Carboniferous. 



Sulcuna, Rhombina J. K. and B. ; Gypresis, Cyprosina Jones. Paleozoic. 



