330 PROCEEDINGS OF THE ACADEMY OF [Nov., 



Length 2, diameter 9 mm. 



Puerto Columbia, dept. Atlantico, Colombia, on limestone hills. 

 Morgan Hebard and J. A. G. Rehn, 1920. Type and paratypes no. 

 46634 A. N. S. P. 



While this species of the subgenus Immersidens is somewhat 

 similar to G. cochisensis, G. daUiana and other North American 

 snails of the same subgenus, it differs remarkably in the palatal 

 folds, the upper being doubled, probably by division of a primi- 

 tively single upper palatal, and the lower fold enters so deeply that 

 its full structure can be understood only by breaking out the palatal 

 wall, as in fig. 4. 



A weak-toothed form of Gastrocopfa senilis (Gld.,) referable to 

 G. s. riisei (Pfr.), was found in the same locality. 



