GASTROCOPTA, NORTH AMERICA, WEST INDIES. 81 



lamella being short, not reaching to the lip, the columellar 

 lamella has no buttress below, and the basal fold is generally 

 wanting. Sometimes, as in the specimens from Navajo 

 Springs, both basal and upper palatal folds are wanting. 



Arizona: Mescal Gulch and drift of Verde River, near 

 Jerome, Yavapai Co. (type loc.) ; Navajo Springs, Apache 

 Co. (Ashmun). 



Bif. hordeocella Pils. var. parvidens STERKI, Nautilus, xii, 

 March, 1899, p. 128. Bifidaria hordeacella parvidens Sterki, 

 PILSBRY and VANATTA, Proc. A. N. S. Phila., 1900, p. 594, pi. 

 22, fig. 2. 



This race, though not rare around Jerome, seems to have a 

 rather restricted area. I have collected for years in the re- 

 gions north and south without encountering it. It has reached 

 about the same stage of decadence as G. servilis riisei in St. 

 Thomas, and differs from that form by the slightly smaller, 

 especially narrower dimensions, and the noticeably deeper 

 suture. No doubt parvidens is a derivative of hordeacella. 



The descriptions of P. jamaicensis and P. ovum-formica:, 

 which I consider synonyms of pellucida, follow: 



"Pupa Jamaicensis. Shell cylindrical; pale brownish-horn 

 color ; with fine oblique striae of growth ; spire tapering only 

 near the summit into an obtuse apex; whorls five, quite con- 

 vex, with a deep suture; aperture semi-oval, with the right 

 side longer, and shouldered above, and the transverse side a 

 little oblique ; to the right of the middle of the latter is a very 

 promient [prominent] stout tooth ; on the middle of the colu- 

 mella is another equally stout, but less prominent; on the 

 right side is another prominent tooth directed between the 

 two above-mentioned, and on each side of it a rather smaller 

 tooth; lip nroderately reflected, with a very small umbilicus. 



"This species is more exactly cylindrical than P. servilis 

 Gould, P. procera Gould, etc., which have a similar aperture; 

 the upper and lower teeth of the right side are more conspic- 

 uous, and the shell is much smaller. Length .07 inch ; breadth 

 .025 inch" [== length 1.75, diam. 0.625 mm.]. Jamaica (C. 

 B. Adams'). 



Pupa pellucida, was not known to Adams when he described 







