BULIMULUS-BOSTKYX-LISSOACME. 193 



Remarkable for its regular, symmetrical form, its coloration and 

 transparence. 



B. HELOICUS Orbigny. PL 51, figs. 12, 13. 



Shell narrowly umbilicated, oblong-conic, thin, substriatulate, as 

 if frosted, corneous- or whitish-yellow. Spire conic, the apex obtuse. 

 Whorls 6?-7, scarcely convex, the last a little shorter than the spire, 

 rotund at base. Columella receding. Aperture little oblique, oval ; 

 peristome simple, thin, the columellar margin dilated above, vault- 

 ingly reflexed. Alt. 24, diam. 10* mill.; aperture 12 mill. long. 6 

 wide. (Pfr.). 



Alt. 25, diam. 1 2 mill. ( Orb.). 

 Mission of Bidosi, Prov. Santa Cruz de la Sierra, Bolivia (Orb.). 



Helix heloica ORD., Mag.de Zool., 1835, p. 11. Bulimus heloicus 

 ORB., Yoy., p. 272, pi. 30, f. 9-11. PFR., Monogr., ii, p. 204; iii, 

 439 ; iv, p. 504 ; vi, 152. Bulimulus heloicus BECK, Index, p. 67. 

 B. heloecus ALBERS. Otostomus heloicus H. ADAMS, P. Z. S., 1866, 

 p. 442. 



It is also recorded from eastern Peru. Subgeneric position un- 

 certain. 



B. TURRITELLATUS Beck. PL 50, figs. 65, 66. 



Shell openly perforate, ovate-conic, rather thin, smooth, subdia- 

 phanous ; corneous gray, ornamented with close white lines. Spire 

 conic and rather acute, the apex pale corneous or roseate. Whorls 

 6, slightly convex, the last slightly shorter than the spire. Col- 

 umella very slightly arcuate. Aperture oblong oval, the peristome 

 simple, unexpanded, columellar margin dilated, somewhat vaultingly 

 spreading. Alt. 21, diam. 10 mill. ; alt. of aperture 11, width 5 mill. 



Province of Chiquitos, Bolivia, near the ancient Mission of San 

 Juan (Orb.). 



Helix turritella ORB., Mag. de Zool., 1835, p. 13. Not Helix tur- 

 ritella Fer. Bulimus turritella ORB., Voy., p. 274, pi. 33, f. 12-14. 

 REEVE, Conch. Icon., pi. 70, fig. 511. PFR., Monogr., ii, p. 208. 

 Bulimulus turritellatus BECK, Index Moll., p. 67. 



Differs from B. sporadicus in the^g^yyj, j^jt^more pupiform 

 shape, and line ornamentation. 

 13 



