BULIMULUS-SOUTH AMERICAN. 67 



nepionic whorls shallowly, rather irregularly zigzag wrinkled in the 

 young, this sculpture lost with age. Whorls 6, convex, with well 

 impressed sutures. 



Aperture ovate, rather wide, brownish inside, varying from slightly 

 to decidedly under half the length of the shell ; outer lip regularly 

 arcuate, acute, unexpanded and fragile, columella slightly concave, 

 the columellar margin narrowly reflexed above. 



Alt. 20, diam. 10s mill.; alt. of aperture 9 mill. 



Alt. 17J, diam. 8 mill. ; alt. of aperture 7 mill. 



Alt. 17, diam. 8f mill. ; alt. of aperture 8 mill. 



Gorritti Island, Maldonado Bay, Uruguay (Dr. Wm.H. Rush, U. 

 S. N.). 



B. gorritiensis PILS., Nautilus, x, p. 78 (name only) ; Proc. Acad. 

 N. S. Phila., 1897, p. 18 (Feb. 23). 



A smaller, thinner, more turrited shell than B. sporadicus or its 

 varieties, the whorls more convex, apex blunter, the first whorl 

 being planorboid. The whorls are more convex and more wrinkled 

 than in thorvyi or tenuissimus. 



B. SPORADICUS (Orbigny). PL 11, figs. 12, 13, 14, 15, 16, 17, 18. 



Shell perforate, oblong-subfusiform, thin, striatulate ; whitish or 

 pale corneous, typically variegated with narrow corneous or brown 

 streaks. Spire elongated, conic, the apex acute. Whorls 7-8, 

 slightly convex, the last about three-sevenths the total alt., attenu- 

 ated at base. Columella somewhat straightened, a little receding. 

 Aperture oval-oblong ; peristome simple, unexpanded, the columellar 

 margin dilated above and reflexed half over the perforation. 



Alt. 32, diam. 12J ; aperture 15 mill, long, 7 wide. 



Prov. Corrientes, Entre-Rios, Buenos Ay res, and south to the Rio 

 Negro, Argentina; Montevideo, Uruguay. 



Helix sporadica ORB., Mag. de Zool., 1835, p. 12. Bulimus sporad- 

 icus ORB., Voy. dans 1'Amer. Merid., p. 271, pi. 32, f. 12-15. PFR., 

 Monogr., ii, p. 201 ; vi, p. 128. HEYNEMANN, Malak. Bl. 1868, p. 

 108, pi. 4, f. 6 (jaw and teeth). HIDALGO, Viaje al Pacif, p. 120. 

 Bulimulus (Thaumastus) sporadicus STROBEL, Mater. Malac. 

 Argent., p. 24 (with var. bonariensis). DOERING, Bol. Acad. Nac. 

 Cien. Rep. Argent., iii, p. 73 (with varr. montevidensis and subtro- 

 picalis). PARAVICINI, Bol. Mus. Zool. ed Anat. Cornp. Univ. Tor- 

 ino, ix, no. 181, p. 6 (1894). Balinus sporadicus SOWB., Conch. 

 Illustr., f. 73-75. Bulimus montevidensis PFR., P. Z. S., 1846, p. 



