90 MOLLUSCA. 
3. Streptostyla dubia. (Tab. V. fig. 10.) 
Spirazis dubia, Pfr. P. Z. S. 1856, p. 378°; Malak. Blatt. 1856, p. 232 *; Monogr. Helic. Vivent. 
iv. p. 580°. 
Streptostyla dubia (Pfr.), Fischer & Crosse, Miss. Scient. Mex., Mollusca, i. p. 65°. 
Hab. Cuiapas (Ghiesbreght 1~*). 
Costulated as in the first two species, but not of the same uniform colouring. 
I am indebted to Mr. Edgar Smith for a figure (fig. 10) and exact measurements of 
this aberrant shell. 
B. Polite. 
[Chersomitra, v. Martens, in Albers’s Die Helic. ed. 2, p. 33 (1860).] 
a. Nigricantes. 
4, Streptostyla nigricans. 
Glandina nigricans, Pfr. P. Z. S. 1845, p. 75"; Albers, Die Helic. p. 197 (1850) *. 
Achatina (Glandina) nigricans, Pir. Monogr. Helic. Vivent. ii. p. 280°. 
Achatina nigricans, Reeve, Conch. Icon. vi., Achatina, t. 14. fig. 54°; Deshayes, in Férussac’s 
Hist. Nat. Moll. Terr. ii. p. 179, t. 137. figg. 9, 10°. 
Spiraxis nigricans (Pfr.), Shuttl. in Bern Mittheil. 1852, p. 204 (Diagn. no. 2, p. 24) °; Notitie 
Malac. ii. p. 14, t. 5. fig. 27; Tristram, P. Z. 8. 1863, p. 418 °. 
Streptostyla nigricans, Fischer & Crosse, Miss. Scient. Mex., Mollusca, i. p. 60, t. 1. figg. 15, 15a 
(living animal)°; v. Mart. P. Z.S. 1875, p. 647°; Strebel, Beitr. Mex. Land- und 
Siissw.-Conch. iii. p. 24, t. 9. figg. 8, 3.a, t. 12. fig. 1114; Jousseaume, Bull. Soc. Zool. Fr. 
iii. p. 169 (1878) ». 
Hab. Tazasco (var. minor, coll. Cuming ®). 
N. Guatemata: Alta Vera Paz (Bocourt®); near Lake Peten (Salvin ®®); Coban 
(Salvin 4, Sarg 11, Conradt); Vera Paz (Boucard 1). 
The locality Vera Cruz given by Pfeiffer!? on the authority of Delattre, and 
repeated by Shuttleworth ®, is very probably an error, being perhaps a misprint for 
Vera Paz. A confusion may have arisen with the following species, as S. nigricans has 
not been found in the State of Vera Cruz by any of the numerous later collectors. 
5. Streptostyla mitreformis. 
Spiraxis mitreformis, Shuttl. in Bern Mittheil. 1852, p. 205 (Diagn. no. 2, p. 25)*; Notitiz 
Malac. ii. p. 14, t. 5. fig. 3°; Pfr. Monogr. Helic. Vivent. iii. p. 473°. 
Streptostyla mitreformis (Shuttl.), Fischer & Crosse, Miss. Scient. Mex., Mollusca, i. p. 62, t. 1. 
fige. 16, 16a‘. | 
Var. minor. 
Streptostyla mitreformis(Shuttl.), Strebel, Beitr. Mex. Land- und Siissw.-Conch. iii. p. 25, t. 9. fig. 5°. 
Hab. E. Mexico: Cordova (Jacot-Guillarmod 1 2%); Toxpam, near Cordova (Sallé *). 
