1906,1/ NATURAL SCIENCES OF PHILADELPHIA. 145 



Near Jerome at Mescal Gulch, Walnut Gulch, Page's ranch, Kirwagen's 

 ranch, and drift of Verde river; Navajo Springs ; Santa Rita mountains; 

 Oak Creek at Owensbys; drift of Little Colorado river at Holbrook; 

 Nogales, both north and south of the international boundary. New 

 Mexico: Mountain station, Oscura mountains, Socorro county; San 

 Rafael, Valencia county; White Oaks, Lincoln county. 



Subgenus CH^NAXIS nov. 



The shell has a large hollow axis, open below, and about one- third 

 the total diameter of the shell, the structure otherwise being like 

 Bifidaria s. str. ; peristome continuous and free. Type, B. tuba. 



The Bolivian Infundibular ia infundibuliformis (Orb.)^ resembles B. 

 iuha in having a very large umbilicus, and we at first thought to asso- 

 ciate the Arizonian species with it; but Infundibularia differs by the 

 strictly conic shell, and in the aperture, which shows but one lamella, 

 a very large angulo-parietal. Other lamellae or plicae, if they exist, 

 must be very deeply immersed, as in the group Immersidens. 



The type of d'Orbigny's species has been lost, and its internal 

 structure is unknown. It was found with Bifidaria nodosaria (Orb.), 

 :a minute species, imperfectly described and figured, but probably not 

 distinct from B. -pelludda (Pfr.). 

 Bifidaria tuba n. sp. Fig. 6. 



Shell cylindric with a short apical cone, openly umbilicate, the um- 

 bilicus nearly one-third the diameter of the shell, penetrating well- 

 like to the apex. Pale brown, smooth, with light growth-lines only. 

 Whorls 5^^, convex, the apex obtuse; last three whorls forming the 

 cylindrical part of the shell. The last whorl is compressed around the 

 umbilicus, and scarcely straightened in front. The aperture is short- 

 oval, the peristome continuous, thin and well expanded. The angular 

 and parietal lamellae are combined into one long lamella, notched on 

 the summit; where the two join, the inner end of the angular projects 

 a little on the right side. The columellar lamella is massive, slightly 

 bifid, deeply placed, and enters about as deeply as the parietal. 

 There are small, short, upper and lower palatal and basal folds, in the 

 typical positions, a short distance within the lip, usually with a minute 

 denticle between them, and another at the base. 



Length 3, diam. L5 mm. 



Drift debris of the San Pedro river, Benson, Cochise county, Arizona. 

 'Types No. 87,062 A. N. S. Phila.; cot5^es in Ferriss collection. A 



'^Voyage dans V Amerique Miridionale, Mollusques, p. 323, pi. 41 bis, fig. 7-10. 

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