a ary 
Plate XV. 
Fig, 1. -Kirkbya subquadrata, n_ sp... =. 1g2 
Ia, 16 and Ic, side, posterior, and dorsal views of a right valve, 
x 28. Falls of the Ohio. 
Hig. 22 Kirkbya: parallelay memsp ee 5p ae ae 192 
2a and 24, side and posterior views of a right valve, x 28. Falls 
of the Ohio. 
Figs. 3 and 4.. Kirkbya semimuralis, n. sp...) =e 193 
3a and 34, side and ventral views, x 28, of a rather short right 
valve. 
4a, 46 and 4c, side, ventral, and posterior views, x 28, of a longer 
and otherwise different right valve. Falls of the Ohio. 
Fig. 5. Halliella retifera, n. gen. et Sp. =. 185 
sa and 54, side and posterior views of a right valve, x 20. 
56 and 5d, ventral and side views of a left valve, x 20. 
5é, interior of another left valve, x 20. Falls of the Ohio. 
Fig. 6. Ctenobolbina informis, n. sp.-2 >. 4.5). =. en 187 
6a, 66 and 6c, side, posterior, and ventral views of a right valve, 
x 20. Falls of the Ohio. 
Fig. 7. Ctenobolbina minima, n. sp... ... >.) 2a9e 188 
A right valve, x 20. 18 mile ereek, Ni W- 
Figs 8. Ctenobolbina papillosa, n. sp... -... 3. 186 
8a, 86 and 8c, side, posterior, and ventral views of a left valve, 
x 20. Falls of the Ohio. 
Fig. 9. Ctenobolbina antespinosa, n. Sp. .... 4:5 eae 187 
ga, 94 and gc, side, dorsal, and posterior views of a left valve, x 20. 
The frill is broken away at the ends. Falls of the Ohio. 
