FKOM NORTH AMERICA, WALES, AND IRELAND. 29 



EXPLANATION OF PLATES I.-IV. 

 Plate I. 



North- American Ostracoda. 



Fig. 1. Kloedenia notata (Hall), var. ventricosa, Hall, a, left ; b, right, valve. 

 (Magnified 4 diam.) 



2. Beyrickia trisulcata. Hall. Left valve. (Magn. 8 diam.) 



3. Beyrichia granulata, 'H.nW. a, left valve (magn. 4 diam.) ; Z>, part of 



surface (highly magnified). 



4. Beyrickia oculina, Hall. Left valve. (Magn. 4 diam.) 



5. Leperditia hiidsonica, Hall, a, carapace (nat. size) ; b, right valve, 



side yiew, and c, edge view (magn. 2 diam.). 



6. Leperditia alta (Conrad), var. a, right valve (nat. size) ; b, inside view 



(magn. 2 diam.). 



[Figs. 1-6 are copied from the original drawings intended for 

 publication in 1859.] 



7. Isochitina Seelyi (Whitfield). Left valve. (Magn. 10 diam.) 



8. IsochUina cristata {Whii^&ld). Right valve. (Magn. 15 diam.) 



9 & 10. Isochitina gregaria (Whitfield). Right valves. (Magn. 15 diam.) 



11. Leperditia hudsonica, Hall, a, right valve; b, edge view; c, end 



view. (Magn. 25 diam.) 



12. Leperditia sinuata, Hall. «, right valve ; 6, edge view ; c, end view. 



(Mngn. 25 diam.) 

 13 & 14. Leperditia seneca, Hall. Right valves. (Magn. 25 diam.) 

 15. Isochilina ?, sp. Right valve. (Magn. 6 diam.) 



Plate II. 



North- American Ostracoda. 



[Figs. 1 a, b, c, are magnified 10 diameters ; all the other figures 25 diameters.] 



Fig. 1. Beyrichia tidjerculata, Boll, var. pustulosa, Hall. Cast, a, right valve, 

 broken in front ; b, edge view ; c, end view, 



2. Primitia seminulum, Jones. Left valve, broken in the middle. 



3. Beyrichia hamiltonensis, sp. nov. Left valve. 



4. Strepula sigmoidalis, Jones. Left valve. 



5. Isochilina lineata, sp. nov. Adult, a, right valve ; b, edge view. 



6. Beyrichia (Bqitilatera, Hall. Cast. Right valve. 



7. Primitiopsis punctulifera (Hall). Young, a, left valve ; b, edge 



view. 



8. Isochilina lineata, sp, nov. Young, a, left valve ; b, edge view. 



9. Entomis rhomboidea, sp. nov. Left ? valve, altered in shape. 



1 0. Entomis rhomboidea, sp. nov. a, left ? valve, less altered ; b, edge 



view. 



11. Isochilina fcdiacea, sp. nov. Left valve. 



12. Primitiopsis punctulifera (Hall), a, left valve ; b, edge view, 



13. Primitiopsis punctulifera (KaXl). a, left valve; 6, edge view of cara- 



pace. 



Plate III, 

 Silurian Ostracoda. 



[All the figures are magnified 15 diameters, except figs. 12^;, 13 b, lAb, and 

 24 b, which are X 70 diameters.] 



Figs. 1, 2,3. Bollia lata (Vanuxem & Hall). Separate valves. 



4-8. Mchinina spinosa (Hall). 4, inside of left valve; 5-8, right 

 valves. 

 9-11. JEchminu Byrnesi (Miller). 9, right valve ; 10, left valve; 11 

 edge view of fig. 10. 



