330 MOLLUSCA. 
Probably also in the Bahamas and Bermudas. Very closely allied forms occur in 
the Old World, in Abyssinia, Southern Arabia, Mesopotamia, British India, Australia, 
and W. Africa [see Jickeli, Land- und Siissw.-Moll. Nordost-Afrikas, p. 99 (1874)]. The 
above description and figure are taken from Mexican specimens collected by Hoge. 
2. Pupoides chordatus. 
Bulimus chordatus, Pfr. Malak. Blatt. 1856, p. 46'; Monogr. Helic. Vivent. iv. p. 420°; Novitat. 
Conch. iii. p. 410, t. 94. figg. 3-6 °. 
Pupa (Leucochila) chordata, vy. Mart. in Albers’s Die Helic. ed. 2, p. 296*; Binney, Land and 
Freshw. Shelis N. Am. i. p. 241, fig. 418°, 
Pupa chordata, Fisch. & Crosse, Miss. Scient. Mex., Mollusca, i. p. 313°. 
Hab. N.W. Mexico: Mazatlan (E. Klocke?~°). 
Fam. ELASMOGNATHA. 
Jaw arcuated, ribbed, produced backwards into a quadrangular plate. Teeth of the 
radula as in the genus felix. 
SUCCINEA. 
Succinea, Draparnaud, Hist. Nat. Moll. Terr. et Fluv. Fr. pp. 24, 58 (1805). 
Shell ovate or oblong, with few whorls and a very large aperture, the margins of the 
latter straight and thin; the whole shell generally unicolorous, yellowish. | 
This genus is cosmopolitan, and most of its species are very much alike. The chief 
specific characters are to be found in the general shape, the greater or less convexity 
of the whorls, and the proportion of the aperture to the whole length of the shell. 
It must be noted, however, that the aperture is placed somewhat obliquely to the axis 
of the shell, and that the length, measured in its own plane, is little more than a 
fractional part of the whole length occupied by it; therefore, in the comparative table 
both measurements are given—the fractional part of the whole length in the column 
‘¢ Apertura,” and the real length measured in the oblique direction in the last column 
but two. 
The sculpture affords few points of distinction, consisting chiefly of the finer or 
coarser strive. 
Geographical distribution, universal, but more common in temperate than in tropical 
zones. Some species common to the Southern States of North America and to Mexico, 
but none of those of the West-Indian Islands appear to be identical with those of the 
mainland of Central America: S. gundlachi, Pfr., from Cuba, however, approaches 
the Mexican S. duteola, A. Gould; S. approximans, Gundl., from Cuba, and S. domini- 
censis, Pir., from Haiti, resemble S. guatemalensis; and S. sagra, d’Orb., approaches 
S. pueblensis. 
