ERRATA. 



The reference to plate 63, on pages 110, 9th line from bot- 

 tom; p. Ill, 16th line from bottom; p. 201, 10th line from 

 bottom, should read PLATE 43. 



In place of the upper line on p. 143, read : 



Section Bactrocoptis Pilsbry, 1902. 



Pilsbry, Man. Conch, xv, pt. 58, p. 112, for U. rosea mon- 

 tana. 



Reference to Map no. 2, on pp. 114 et seq., should read 

 Map no. 1. 



On p. 205, fig. 25 should be deleted from the line under 

 head of U. NOTATA. 



On pp. 211, 232, reference should be made to the dentition 

 of U. garciana, figured on pi. 43, f . 2 ; and on pp. 268, 270, to 

 that of U. gracillima, figured on pi. 50, f. 11. In this species 

 the radula is specialized less than in those mentioned on 

 p. 268, 



(viii) 



