308 MOLLUSCA. 
Spiraxis, Sect. I. Species Torto-plicate, Fischer & Crosse, Miss. Scient. Mex., Mollusca, i. pp. 608, 
609. 
Volutaxis, Strebel, Beitr. Mex. Land- und Siissw.-Conch. v. p. 110 (1882). 
Shell turrite, imperforate, vertically striate or ribbed, thin, glossy, whitish or yellow ; 
whorls 5-13, increasing very gradually in diameter, more or less flat; aperture com- 
paratively small, generally only one-fourth or one-fifth of the length of the whole shell ; 
columellar margin spirally twisted, more or less thickened, without notch at the base. 
Anatomy not yet known. The natural position of this genus is therefore still doubtful. 
In some respects it comes very near Opeas, several species having the spiral twisting of 
the columellar margin less distinct and the brightness of the surface less conspicuous ; 
but in the majority of them the general aspect is different and well recognizable. 
Shuttleworth united them with the agnathous Streptostyla into one genus, and Strebel 
says also (loc. cit. p. 117) that his Volutaxis belongs, according to its anatomy, to the 
Testacellide, but he gives no anatomical description of any of his species. 
Geographical distribution: West Indian islands and Central America, passing neither 
to North nor to South America *. 
1. Spiraxis scalariopsis. 
Bulimus scalariopsis, Morelet, Test. Noviss. ii. p. 11 (1851)'; Pfr. Monogr. Helic. Vivent. iii. p. 895°. 
Spiraxis scalariopsis, Fisch. & Crosse, Miss. Scient. Mex., Mollusca, i. p. 609, t. 25. figg. 1, la, 6°. 
Hab. N. GuatemMaua: Peten, in very thick forests, under decaying trunks of trees 
(Morelet 1-8). | 
2. Spiraxis sulciferus. (Tab. XVIII. fig. 4.) 
Bulimus sulciferus, Morelet, Test. Noviss. ii. p. 12 (1851)’; Pfr. Monogr. Helic. Vivent. iii. 
p. 895°. 
Spiraxis sulciferus, Fisch. & Crosse, Miss. Scient. Mex., Mollusca, i. p. 610, t. 25. figg. 2, 2a, 6°. 
Volutaaxis sulciferus, Strebel, Beitr. Mex. Land- und Siissw.-Conch. v. p. 120, t. 7. figg. 10a, 108, 
t. 17. fig. 12 *. 
Spiraxis euptyctus, Pfr. P. Z. 8. 1856, p. 378°; Malak. Blatt. iii. p. 2832 (1856)°; Monogr. Helic. 
Vivent. iv. p. 574"; Fisch. & Crosse, loc. cit. p. 612°. 
Hab. Ei. Mexico: Rancho de Guerrero, Rancho de San Eligio, and Agua Caliente near 
Misantla (Estefania Salas*) ; Mirador (Berendt®). 
S.E, Mexico: Palenque, in woods (Morelet 1); Chiapas (@hiesbreght >-8). 
W. GuatemaLa: Retalhuleu, in the woods (St¢old). 
Var. cobaensis. 
Spiraais sulciferus, var. 8. cobanensis, Fisch. & Crosse, loc. cit. pp. 610, 611, t. 25. figg. 3, 3a, b*. 
Hab, N. GuatemMaLa: Coban (Sarg °). 
* Spiraxis equatorius, Miller, from Ecuador, belongs to Leptinaria. WS. incertus, Mouss., from Colombia, 
and the East-Indian species referred by Pfeiffer to this genus probably do not belong to it. 
