INDEX TO PLATES. 



PLATE I. 

 HELIX MAJOR Binney, p. 96. 



PLATE II. 



HELIX ALBOLABRIS Say, with the animal. Lingual 

 teeth, p. 102. The arrow indicates the central range ; a, 

 the lateral portion, the continuation of which is placed 

 above ; b, a longitudinal series of hooks, showing their in- 

 clination forwards, p. 99. 



n-t 

 \. I .-? 



PLATE III. 

 HELIX MULTILINEATA Say, with the animal, p. 103. 



PLATE IV. 



HELIX CLAUSA Say. Hypopus concolor, Haldeman, 

 the minute acaridian which infests the animal of this and 

 other species, p. 107. 



PLATE V. 



HKLIX COLUMBIANA Lea, p. 169. 



VOL. III. 4 



