OTOSTOMUS. 217 
This species almost forms a connecting-link between O. attenuatis, O. serperastrum, 
and O. pallidior, Sow., the latter from the Peninsula of Lower California; it resembles 
0. attenuatus, but has not its thread-like, twisted, columellar margin. From 0. pallidior 
it Ls distinguished by the less conical, in the last whorl much more oblong, form, the 
thinner shell, and the narrower aperture; from 0. serperastrum also by the general 
shape of the shell. Some specimens are entirely white; others have more or less 
distinct traces of pale brown spots on the penultimate whorl arranged in four spiral 
rows, corresponding in position to those of O. serperastrum (the fifth and sixth being 
covered by the following whorl), but they do not extend over more than half the whorl 
in the spiral direction. 
24. Otostomus hepatostomus. (Tab. XIII. figg. 18-20.) 
Bulimus hepatostomus, Pfr. P. Z. S. 1861, p. 23, t. 3. fig. 44; Malak. Blatt. viii. p. 13 (1861) *; 
Monogr. Helic. Vivent. vi. p. 43°. 
Bulimulus (Drymeus) hepatostomus, Fisch. & Crosse, Miss. Scient. Mex., Mollusca, 1. p. 493, t. 21. 
figg. 2, 2a’. 
Hab. S. Mexico: Tepanistlahuaca (Boucard'~*); Juquila, State of Oaxaca (Hége). 
Nearly allied to O. attenuatus, but less attenuated, also somewhat variable in form. 
The brownish hue of the inside of the aperture is in some specimens very distinct, in 
others scarcely to be seen. On the outside of the second half of the last whorl the 
shell becomes in some examples rather wrinkled. 
25. Otostomus costaricensis. 
Bulimus costaricensis, Pfr. in Malak. Blatt. ix. p. 153 (1862) *; Monogr. Helic. Vivent. vi. p. 47°; 
Novit. Conch. iii. p. 419, t. 95. figg. 11, 12°; Angas, P. Z. S. 1879, p. 478°. 
Bulimulus (Drymeus) costaricensis, Patel, Catalog. p. 100°. 
Bulimus navarrensis, Angas, P. Z. S. 1878, p. 78, t. 5. figg. 15, 16°. 
Hab. Centra Costa Rica: San José (Pittier and Biolley) ; San Francisco de los Rios, 
near San José, on hedges (Pittier) ; Alajuela at an elevation of 900-1000 metres 
above the sea (Orosco) ; Cartago and Navarro (Boucard®); elevated plain of Costa 
Rica (Hoffmann). 
Costa Rica, without nearer indication of locality (von d. Busch 1~*), 
Very near 0. attenuatus and O. hepatostomus, but less attenuated, and with the 
stripes more interrupted, appearing in the upper whorls rather like interrupted spiral 
ize and proportional breadth: see the measurements given 
bands. Rather variable in si 
in the Table of species (anted, p. 195). Most of the specimens I have seen are somewhat 
more elongated and less ventricose than Pfeiffer’s original type 1~*; but there are many 
gradations in this respect. 
BIOL. CENTR.-AMER., Terr. and Fluviat. Mollusca, September 1893. 98 
