Xu-MKKR 135 February 25. 1923 



OCCASIONAL PAPERS OF THE MUSEUM OF 

 ZOOLOGY 



UNIVERSITY OF MICHIGAN 

 Ann Arbor, Michigan Published by the University 



THE MOLLUSCA COLLECTED BY THE UNIVER- 

 SITY OF AIICHIGAN-WALKER EXPEDITION IN 

 SOUTHERN VERA CRU-Z, MEXICO, IV 



By H. Burrington Baker 



The introduction and parts I, II, and III of the present 

 paper appeared as number 106 of this series (Feb. 18, 1922). 

 The habitat references (preceded by H) are explained in the 

 introduction. Attention is called to the following errata in 

 the preceding" parts : 



Page 8, 5 lines from bottom: (?) to precede U. plicatidus. 



Pages 10, II, 12: E. p. crocodilonim, not crocodilariim 

 (corrected by L. S. Frierson, in letter). 



Pages 24, 25, 27: Ayotonaias, not Artonaias (correction 

 due to L. S. Frierson). 



Page 47, 6 lines from bottom : Dry Dice us, not Dryuiacits. 



Pages 48, 49 : B. elegantulus, not elcgantida. 



Page 56, 5 lines from bottom : T. honiii, not kornii. 



