PLANORBIS. 21S 



PLANORBIS. 



Synonymy and Reference to 

 Plate 7. 



Fig. 



1 — 3. Pl. opercularis, Gould. Proc. Bost. 



Soc. ii, 212, 1847. 



Binney, 1. c. 125. No. 19. 



4 — ^6. Pl. vermicularis, Gould. Proc. Bost. 

 Soc. ii, 212, 1847. 

 Binney, 1. c. 128. No. 21. 



7 — 9. Pl. Centervillensis, Try on. This 

 work, p. 210. No. 24. 



Pl. parvus. Say. Hald. Monog. p. 27, 

 t. 4, f. 19—23. 

 10. Pl. Billingsii, Lea. Philad. Proc. iii, 

 1864. 

 Observ. xi, 115, t. 23, f. 72. No. 26. 

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