OPEAS. 291 
This family nearly corresponds to the genus Stenoyyra, proposed by Shuttleworth in 
1§54; but as his subdivisions are at present regarded as distinct genera, and these have 
names of older date, Stenogyra as a generic term cannot be employed. ‘These genera, 
typically, are well defined by the shape of the columellar margin (pillar-lip) of the 
aperture; but in some aberrant species the differential characters are considerably 
modified, so that even the distinction between Opeas and Leptinaria is in some 
instances not very obvious. 
OPEAS. 
Bulimus, subgen. Opeas, Albers, Die Heliceen, ed. 1, p. 175 (1850). 
Stenogyra, sect. Opeas, Shuttleworth, in Mittheil. nat. Ges. Bern, 1854, Diagn. no. 6, p. 137; 
Albers, Die Heliceen, ed. 2, p. 265. 
Opeas, Fischer & Crosse, Miss. Scient. Mex., Mollusca, i. p. 592; Strebel, Beitr. Mex. Land- und 
Stissw.-Conch. v. p. 98. 
Shell more or less turrite, with simple columellar margin, not notched, toothed, or 
strikingly twisted: most of the species with a narrow perforation. 
For the anatomy, see the quoted works of Fischer and Crosse, pp. 593-595, and 
Strebel, pp. 101, 105. 
Circumtropical. 
The columellar margin appears to be straight and vertical, attenuated towards the 
base if viewed at a right angle to the plane of the aperture; butif examined obliquely, 
and thus deeper into the interior of the aperture, the margin is seen to be somewhat 
spirally twisted. 
In order to indicate the differences in the form of the spire by distinct numbers, I 
use in this and the following genera the proportion of the last whorl in height, as 
seen from the dorsal side (the side opposite to the aperture), to the whole length of 
the entire shell. 
The generic name is the Greek word for an awl, and neuter. 
1. Opeas subula. (Lab. XVIII. fig. 3.) 
Achatina subula, Pfr. in Archiv f. Naturg. 1839, p. 352’. 
Bulimus subula, Pfr. Symb. Hist. Helic. i. p. 25%; Monogr. Helic. Vivent. ii. p. 158°; Reeve, 
Conch. Icon. v., Bulimus, t. 69. fig. 494°. 
Bulimus (Opeas) subula, Albers, Die Helic. ed. 1, p. 175 ®; Crosse & Fisch. in Journ. de Conch. 
xi. p. 361, t. 14. fig. 6 (1868) °. 
Stenogyra (Opeas) subula, Shuttleworth, in Mittheil. nat. Ges. Bern, 1853, Diagn. neuer Moll. no.5, 
p. 1887; v. Mart. in Malak. Blatt. xii. p. 49 (1865)°; Binney, Terr. Air-breath. Moll. 
N. Am. v. p. 195, fig. 99°; Manual Am. Land-Shells, p. 426, fig. 473 (1885) *. 
Opeas subula, Fisch. & Crosse, Miss. Scient. Mex., Mollusca, i. p. 600, t. 26. figg. 7, 7 a, 6, and t. 28. 
figg. 11-13 (jaw and radula, copied from Binney)”; Strebel, Beitr. Mex. Land- und Siissw.- 
Conch. v. p. 163, t. 7. fig. 1, t. 17. fig. 27 > Ancey, in Ann. de Malac. 1886, p. 250”. 
37* 
