GASTROCOPTA, NORTH AMERICA, WEST INDIES. 59 



Length 2.5 to 2.2 mm. 



South Carolina to the keys of south Florida, west along the 

 Gulf coastal plain to Galveston, Texas. Bermuda. North Cat 

 Cay, Bimini group, Bahamas. Type locality, ruins of Fort 

 Picolato, St. John's River, Florida. 



Pupa rupicola SAY, Journ. Acad. Nat. Sci. Phila., ii, 1821, 

 p. 163. GOULD, Boston Journal of Natural History, iv, 1843, 

 p. 355, pi. 16, f. 13. BINNEY, Terr. Moll., iii, pi. 70, fig. 1 

 (left and central figs. ) . STERKI, Nautilus, iv, 1891, p. 139. 

 Bifidaria rupicola (Say), PILSBRY and VANATTA, Proc. A. N. 

 S. Phila., 1900, p. 595, pi. 22, f. 1. 



This species tapers upwards much more than G. procera, 

 which is subcylindric. G. servilis has a thinner lip. In G. 

 rupicola the outer and basal margins of the peristome are 

 spreading, broad, and conspicuously thickened by a heavy 

 white callous within the sharp edge. This callous is narrowed 

 near the posterior angle as usual. The angulo-parietal lamella 

 shows a small lateral spur in the front view. Seen from 

 below (pi. 11, fig. 6) it is very slightly sinuous, nearly 

 straight except in front, where it curves outward to unite 

 with the outer lip. The columellar lamella consists of a very 

 low, vertical portion which bends forward below, forming a 

 strong horizontal portion (fig. 5). The lower palatal plica is 

 not much lengthened, but is larger and more deeply placed 

 than the upper. There is a narrow and low but distinct crest 

 close behind the lip, and a flattening over the position of the 

 lower palatal plica. Length 2.5, diam. 1.1 mm.; 5% whorls. 

 The color varies from very pale brown to corneous, the sur- 

 face being very finely, rather irregularly striate. 



In some places the average size is smaller, as at Miami, 

 Florida. In other colonies, as at Lossman's Key, in the Ten 

 Thousand Islands (pi. 11, fig. 1; length 2.2 mm., 5 whorls) 

 both the maximum and the minimum sizes were found living 

 together, the smallest 2.1 mm. long. There is a more or less 

 developed callous buttress under the inner end of the parietal 

 lamella in this and some other lots, while in typical rupicola 

 it is absent or only weakly developed. 



PL 11, fig. 3, is abnormal in having the lower palatal plica 

 doubled, but such abnormalities are not uncommon. 



