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PROCEEDINGS OF THE NATIONAL MUSEUM 



VOL. 85 



flutings. The shell, as a rule, is interruptedly spirally banded, the 

 spiral bands varying decidedly in conspicuousness, sometimes being 



FiGUUE 77. — Distribution of tho subspecies of Chondrnpometcs (Chondrotlvjroma) mag- 

 num: (1) eUsabethae; (2) sUjnac; (?,) magnum. 



almost absent. The segments are usually arranged in vertical series, 

 which gives the shell a somewhat axially banded aspect. 



This subspecies, we believe, ranges around the inner rim of the 

 Portrero de Luis Lazo, including the Sierra de los Acostas, Sierra 

 de San Carlos, and i\\Q Sierra del Sumidero. 



The type, U.S.N.M. no. 355017, was collected on the vrest side of 

 the Luis Lazo embrasure. It is almost complete and should have 



