426 MOLLUSCA. 
- Geographical distribution nearly universal, but wanting on the continent of South 
America; well represented in North America, one species in the West Indies (Cuba), and 
one in Mexico. This latter is apparently not found in the lakes of Central Mexico, where 
large species of Planorbis, nearly allied to those of North America, are found in plenty. 
1. Vivipara inornata. 
Vivipara inornata, Binney, Am. Journ. Conch. i. p. 49, t. 7. fig. 1 (1865)*; Land and Freshw. 
Shells N. Am. iii. pp. 113, 114, fig. 225’. 
Paludina inornata (Binn.), Fisch. & Crosse, Miss. Scient. Mex., Mollusca, 11. p. 291 *. 
Minutely perforate, globose-ovate, smooth, polished, greenish or pale olive, without spiral sculpture or spiral 
bands; whorls about 5, very convex; aperture exceeding half the length of the shell. Long. 19, 
diam. 17 millim. 
Hab. Mexico: Chopatilo *?!~*. 
Paludina carinata, Valenciennes, in Humboldt and Bonpland’s Obs. Zool. ii. p. 252, 
t. 56. fig. 2 (1839), given by the authors as Mexican, belongs, without doubt, to 
the well-known V. costata, Quoy and Gaimard, from the Philippines; H. ovum 
and H. stolephora, Val., described in the same work, are also Philippine shells 
(cf. v. Mart. Malak. Blatt. xii. p. 71). 
VALVATA. 
Valvata, O. F. Miller, Verm. Terr. et Fluv. ii. p. 198 (1774), auct.; Fischer & Crosse, Miss. 
Scient. Mex., Mollusca, ii. p. 293 (full description and historical account). 
Shell discoidal or depressed conoidal, of rather small size, umbilicate, unicolorous 
brownish ; aperture circular, somewhat parallel to the axis of the whorls (thus differing 
from that of Cochliopa and of the smaller species of Planorbis). Operculum circular, 
thin, corneous, multispiral, with central nucleus. In addition to the one pair of long, 
slender feelers, a third feeler-like organ and a fine feather-shaped gill are exserted 
from the respiratory cavity when the living animal is fully developed. Hermaphrodite. 
Widely distributed in the northern hemisphere ; no species known from Cuba, Haiti, 
or Puerto Rico, the two Jamaican forms described by C. B. Adams perhaps not really 
belonging to this genus. 
1. Valvata humeralis. 
Valvata humeralis, Say, in New Harmony Disseminator of Useful Knowledge, ii. p. 244 (1829)'; 
Menke, Zeitschr. f. Malak. ii. p. 129 (1845) °*; Binney, Land and Freshw. Shells of N. Am. 
ii. p. 14°; Pilsbry, Proc. Acad. Phil. 1891, p. 326‘; Fisch. & Crosse, Miss. Scient. Mex., 
Mollusca, ii. p. 803°. 
* As noted by Fischer and Crosse*, the orthography of this word is probably incorrect. Dr. Seler informs 
me that there is a Rancho named Chapotillo, near Sinaloa, in N.W. Mexico, a Hacienda Chapotito at Cerralvo, 
in Nuevo Leon, near the Rio Grande del Norte, and a Rancho Chapotita in Michoacan, 8.W. Mexico. It is 
most probable that a locality in N.E. or N.W. Mexico is meant, 
