GIBBULINA. 5 



2b. Specimens from the Eagle Tail Mountains, 12 miles 

 north of Kofa, Yuma Co., in moist places among piles of loose 

 rock covered by decayed cactus, elevation about 2000 ft. (G. 

 S. Hutson), and also one of those opened from Tucson, have 

 the internal lamella only about a whorl long or less, but they 

 have the cylindric shape and well-developed supracolumellar 

 nodule of intuscostata. It is an intermediate form between 

 intuscostata and brevicostata, but whether racially distinct I 

 am not prepared to say. 



Genus GIBBULINA Beck. 



Gibbulina BECK, Index Molluscorum, 1837, p. 81. GRAY, 

 P. Z. S., 1847, p. 176 (P. infundibuliformis selected as type). 



Infundibularia PFEIFFER, Malak. Blatter, xxiii, 1876, p. 

 213 (monotype P. infundibuliformis Orb.). 



The shell is minute, broadly umbilicate, conic, thin, the 

 whorls (6 in the type species) convex, of small caliber. Aper- 

 ture small, lateral, oblong, obstructed by a large, deeply en- 

 tering parietal lamella ; peristome expanded and thick. Type 

 G. infundibuliformis. 



The status of this Bolivian group is uncertain, but the 

 known characters, so far as they go, suggest that it may be a 

 derivative of Gastrocopta, either directly related to Ch&naxis 

 or possibly Immersidens, or a modification parallel to the 

 former. If so, it will probably prove to have deeply immersed 

 columellar and palatal teeth. As the type specimens of the 

 only species are lost, these questions must remain in abeyance. 



Gibbulina was established by Beck as a subgenus of Pupa 

 with the following species : 



G. infundibuliformis (d'Orb.). G. palanga (Fer.). 



G. lyonetiana (Pallas). G. iulus B. 



G. pagoda (Fer.). G. palangula (Fer.). 



G. filosa (Valenc.). G. modiolus (Fer.). 



G. inflata (Valenc.). G. modiolina (Fer.). 



G. sulcata (0. Mull.). G. versipolis (Fer.). 



From these, Gray selected the first, G. infundibuliformis as 

 type, in 1847. This invalidates the subsequent general use of 

 the name Gibbulina for a group of Mascarene Streptaxidce. 



