Paleozoic Bivalved Entomostraca. 349 
EXPLANATION OF THE PLATES. 
(The specimens here figured, except figs. 7, 8, and 9 of Pl. XIX., either 
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are or will be deposited in the British Museum.) 
Puate XIX, 
Leperditia balihica (Hisinger), small individual, natural size. 
Upper Silurian; Wren’s Nest, Dudley. a, lateral view ; 6, dor- 
sal view. és 
. Leperditia balthica (His.), var. contracta, nov., right valve, nat. 
size. Upper Silurian, Wren’s Nest. a, lateral; 6, ventral view. 
. Leperditia balthica (His.), var. contracta, noy., internal cast of a — 
right valve (somewhat crushed), magnified 4 diam. From the 
Lower-Ludlow beds at Leintwardine, near Ludlow. 
. Leperditia balthica (His.): a and 6, outlines of two specimens of 
left valves, of different sizes, and both more or less damaged, 
and 4 6, more ovate, probably in consequence; magnified 11 
diam. Uppermost Silurian; from the Bromyard and Worcester 
railway. 
. Leperditia Hisingert (°), Schmidt, small pore of aright valve, 
magnified 2 diam. From the Upper Llandovery of Eastnor, 
near Malvern. a, lateral; 0, anterior view. 
. Leperditia Hisingert, Schmidt, var. gracilenta, internal cast of a 
left valve, magnified 2 diam. Upper Silurian; Kington, 
Herefordshire. a, lateral; 6, ventral; c, anterior view. 
. Leperditia fabulites (Conrad), var. josephiana, Jones, perfect cara- 
pace, with left valve exposed, nat. size. Lower Silurian ; 
St. Joseph’s Island, Canada. a, lateral; 5, ventral view. 
. Leperditia fabulites (Conrad), var. anticostiana, Jones, perfect 
carapace, left valve exposed, nat. size. Lower Silurian; Anti- 
costi, Canada. a, lateral; 6, ventral view. 
. Leperditia amygdalina, Jones, perfect carapace; exposing left valve, 
nat. size. Lower Silurian; L’Orignal, Canada. a, lateral view ; 
6, ventral edge of the left (overlapped) valve; ce, ventral edge of 
the right (overlapping) valve. 
. Leperditia balthica (His.), small, left valve broken at the hinder 
margin, nat. size. Upper Silurian; from Wisby, Gothland. 
. Leperditia balthiea (His.), small, right valve, nat. size. Upper 
Silurian; Wisby. a, side view; 6, ventral outline. 
. Isochilina punctata (d’Kichw.), outline of the inside of a hollow 
cast of the fore part of a left valve, magnified 4 diam. Lower 
Silurian ; Gatschina, near Saretsche, Russia. 
. Leperditia balthica (His.), var. contracta, noy., outline of a right 
valve, magnified 9 diam. Upper Silurian; Talkof, Livonia. 
. Leperditia balthica (His.), var. contracta, nov., outline of a partly 
imbedded right valve, with eye-spot and muscle-spot, magnified 
23 diam. Upper Silurian; Kamenetz-Podolsk. 
. Leperditia phaseolus (His.), outline of a right valve, with eye- 
spot and muscle-spot, magnified 6 diam, Upper Silurian; Ran- 
difer, Oesel. 
Leperditia Hisingert, Schmidt, var., outline of a left valve, with 
eye-spot and muscle-spot, magnified 6 diam. Upper Silurian ; 
Randifer, Oesel. 
Leperditia balthica (His.), var. contracta, novy., left valve, with 
the shell broken in the middle, also imbedded below and be- 
hind, 
