BULIMULUS-SOUTH AMERICAN. 65 



times nearly vertical. Aperture oval, colored like the exterior, one- 

 half the shell's length ; peristome simple, unexpanded, acute, the 

 right margin regularly arcuate, columellar margin reflexed above, 

 nearly covering the perforation. Alt. 17, diam. 9 mill. {Hidalgo}. 

 Rio Janeiro (type locality ; Orbigny, Paz and Martinez) ; Bahia 

 (Paz and Martinez, Moricand, Challenger) ; Pernambuco (Petit). 



Helix tenuissima (Fer.) ORB., Mag. de Zool., 1835, p. 11 (name 

 only). Bulimus tenuissimus (" Fer., dans sa collection ") ORB., Voy. 

 p. 272. B. tenuissimus (" Fer. ex fide Orb.") POTIEZ & MICHAUD, 

 Galerie des Moll, du Mus. de Douai, i, p. 158, pi. 15, f. 19, 20 

 (1838). HIDALGO, Viaje al Pacif., p. 119. SMITH, P. Z. S., 1884, 

 p. 280. Bulimulus thoreyi BECK, Index Moll., 1837, p. 67 (name 

 only). Bulimus thoreyi Bk., PFR., Monogr., iv, p. 500. Not B* 

 tenuissimus Fer., Histoire, pi. 142B, f. 8. 



More or less doubtful references : Bulimus corneus POT. & MICH., 

 Galerie, i, p. 137, pi. 14, f. 11, 12, 1838 [from Cayenne ; name preoc.]. 

 Bulimus tenuis DKR., MS., olim, in Albers, Die Hel., 1850, p. 166, 

 and note 2 on p. 168 [from near Angostura (Gruner) ; not described]. 

 Bulimus tenuissimus FER., Hist., pi. 142 B, f. 8. PER., Monogr., 

 ii, p. 218 ; iii, 439 ; iv, 504 ; vi, 152. TATE, Ann. Mag. N. H. (4), 

 iv, 1869, p. 356. SMITH, Ann. Mag. N. H. (6), iii, p. 403. Cow/. 

 also, REEVE, f. 288, and Conchyl. Cab., p. 241, pi. 63, f. 25, 26. 

 SMITH, Proc. Malac. Soc., i, p. 316. CROSS E, Journ. de Conchyl., 

 1890, p. 43 (Journ. of Conch., viii, p. 241). 



See pi. 14, figs. 9, 10. Smaller than B. barbadensis, with more 

 convex whorls, finer apical sculpture and a gray rather than russet 

 color ; the surface has the dull " bloom " of a plum, a little scratched 

 in places showing the glossy surface below. The figures on pi. 10 

 are from Pot. & Mich., and are not typical. Those on pi. 14 were 

 drawn from " topotypes " collected at Rio Janeiro by Dr. von Iher- 

 ing. Other localities given for the species are Huanuco, Peru 

 (Fontaine, see Orb.) and Bolivia, given by Orbigny in his pre- 

 liminary '' Synopsis " but omitted by him in the " Voyage," probably 

 because the shells proved distinct on further investigation. 



The descriptions of Potiez and Michaud and of d'Orbigny were 

 the first to be published, although there was a Helix tenuissima in 

 Ferussac's collection prior to d'Orbigny's publication. The date of 

 Ferussac's plate 142 B, on which H. tenuissima Fer. first appeared 

 is unknown ; but as that illustration is quoted neither by d'Orbigny 

 nor by Potiez & Michaud, (who elsewhere cite freely earlier plates 

 5 



