BULLA. 331 



B. rubiginosa Gld., Proc. Bost. Soc. Nat. Hist, iii, p. 107, Apr., 

 1849 ; U. S. Expl. E.Kped., p. 221, f. 266, 266a.— Morch, Mai. Bl. 

 xxii, p. 174. — Bulla {Bullea) sulcata Menke, Zeitscbr. f. Mai. 1853, 

 p. 138. 



I have not seen this species, which is evidently a near ally of B. 

 amygdala, if not identical with it. Menke thus describes B. sulcata : 

 "Shell oblong-elliptical umbilicated at vertex, rather solid, dis- 

 tinctly and closely, transversely striated below, longitudinally irre- 

 gularly and more or less obviously subsulcate ; lip somewhat 

 straightened in the middle; rufous-ashy. Length 13, diam. 7 lines. 

 Hab., salt lake at S. Pedro dos Indios, near Cabo Frio, coast of 

 Brazil. The deep longitudinal furrows, always most pronounced on 

 the back and outer lip, distinguish this species. The thin callus of 

 the inner lip ascends to the apical umbilicus, sometimes even in- 

 vading it." 



B. occidentalis a. Adams. PI. 38, figs. 51, 52, 53, 55, 56, 57- 



60 ; pi. 39, figs. 77, 78. 



Shell excessively variable in size, solidity and coloring, but distin- 

 guished from B. driata by (1) the narrower umbilicus, (2) the 

 absence or obsolescence of transverse grooves near the vertex, (3) 

 the less attenuated posterior end [in all of which it is more like the 

 Algerian variety mentioned under B. striata']. It is distinguished 

 from B. amygdala by its thinner, more shining, microscopally spiral- 

 led shell. 



Some form.s are small, very thin, fragile, subcylindiical, densely 

 wave-striated spirally throughout, with the basal grooves scarcely 

 differentiated (pi. 38, fig. 60, pi. 39, f. 78, from a Lake Worth, E. 

 Florida specimen). Some are solider, with close zebra stripes (pi. 

 38, f. 59) as in certain Bahama shells. The prevalent form along 

 the mainland, Texas to Aspinwall and Trinidad, is larger and moder- 

 ately solid, (\) closely mottled with reddish and white (figs. 51, 52, 

 Vera Cruz) or olivaceous and white, or (2) mottled with olivace- 

 ous and clouded Avith black and white (figs. 53, 55, 56, Pro- 

 greso, Yucatan). In unworn examples microscopic spiral striae may 

 be seen over the whole surface, and also basal spaced grooves, but 

 the latter are sometimes very weak and hardly seen on the small 

 thin forms from Florida. The coarser shells sometimes show some 



