154 MOLLUSCA. 
the shell, from very obtuse to sharply keeled, and in the more or less elevated spire. 
On this account they have been widely separated by previous authors, /. bicincta having 
been placed with Arionta or Leptarionta (Fischer), H. trigonostoma with the Papuan 
Geotrochus, and H. guillarmodi with the Philippine Corasia. But I hesitate to admit 
“into one natural subgenus terrestrial species which are geographically so widely 
separated unless they are connected one with another by Palearctic and Nearctic forms, 
giving them a cosmopolitan distribution, as is the case in Patula, Succinea, and Hyalina, 
or unless their real affinity is proved by anatomical investigation. 
Perhaps also the Brazilian H. bifasciata, Burrow, and H. lonchostoma, Menke, may 
find their natural place in this subgenus, although they are somewhat peculiar in their 
general aspect. Anatomical investigation will confirm or disprove this proposition, 
suggested by the knowledge of the shells only. 
93. Helix trigonostoma. (Tab. IX. figg. 1, 1a—9, 9a, 11, 12.) 
a, typica: late trochiformis, subangulata, albida, fasciis fuscis, basi latioribus. 
Helix trigonostoma, Pfr. in Philippi’s Abbild. neuer Conch. i. p. 154, t. 4. fig. 8 (1844) *; P. Z. S. 
1845, p. 41°; Monogr. Helic. Vivent. i. p. 229°; im Martini & Chemnitz, Syst. Conch.- 
Cab. ed. 2, Helix, i. p. 282. no. 282, t. 49. fig. 10°; Reeve, Conch. Icon. vii., Heliz, 
t. 105. fig. 584°, 
Helix (Geotrochus) trigonostoma (Pfr.), Fisch. & Crosse, Miss. Scient. Mex., Mollusca, i. p. 291, 
t. 11. fig. 6°. 
Hab. N. Guatemata: forests of Peten (Morelet®); Senahu, north side of the Polochic 
valley above Panzos (Champion); Vera Paz (Stoll); ‘‘ Prope Vera Cruz, in prov. 
Honduras, Am. Centr.” (Cuming, Pfeiffer?—>), probably Vera Paz is intended. 
Honpuras: on the leaves of trees (Delattre °). 
b. elevato-conica : elevato-trochiformis, non angulata, fasciis fuscis, basi latioribus. 
Helix lailiana, Tristram, P. Z. 8. 1861, p. 230% (misprint for salleana). 
Helix trigonostoma, var. y. elevato-conica, Fisch. & Crosse, loc. cit. p. 291, t. 11. fig. 6a". 
Hab. N. GuatEMALA: mountains of the department of Vera Paz (Bocourt ®); Coban 
(Conradt). 
CENTRAL GUATEMALA: near the city of Guatemala, 5000 feet above the sea (Stoll). 
c. salleana: globoso-trochiformis, flavescens, fasciis virescentibus. 
Heliz salleana, Pfr. P. Z. S. 1849, p. 129°; Monogr. Helic. Vivent. iii, p. 178°; in Martini & 
Chemnitz, Syst. Conch.-Cab. ed. 2, Heliz, ii. p. 281. no. 766, t. 124. figg. 17, 18°. 
Helix trigonostoma, var. ¢. salleana, Fisch. & Crosse, loc. cit. p. 291 ”. 
Hela trigonostoma, var. n. obscura, Fisch. & Crosse, loc. cit. p. 291, t. 11. fig. 6d™. 
Hab. K. Guatemata: Sierra del Mico, south of the Golfo Dolce (Sallé 12) ; “in ripis 
fluvii San Juan, Guatemale ” (Sadlé 9-1), 
S. GuatemaLa: San Agustin (Bocourt 1°), 
