394 MOLLUSCA. 
Hab. §.W. Mexico: Cacoprieto, on the Isthmus of Tehuantepec (Sumichrast *). 
N. Guatemata: Lago de Itza, Peten (Morelet } ). 
CrntraL Costa Rica: near San José, in the Rio Torres and in some pools which 
receive their water from that river (Biolley °). 
S.W. Cosra Rica: Laguna between Lagarto and Boruca (Pittier). 
13. Planorbis e#ruginosus. 
Planorbis eruginosus, Morelet, Test. Noviss. ii. p. 15 (1851)'; Fisch. & Crosse, Miss. Scient, 
Mex., Mollusca, ii. p. 74, t. 82. figg. 8, 8 a, b,c’. 
Right side rather flat, left broadly excavated. 
Hab. N. Guaremata: in marshes adjoining the Lake of Yzabal (Golfo Dulce) 
(Morelet ! *). 
CENTRAL GUATEMALA: Guatemala city, in wells (Stold). 
Morelet’s specimens exhibit a rusty, Stoll’s a blackish incrustation. 
14. Planorbis parvus. 
Planorbis parvus, Say, in Nicholson’s Encycl. (Amer. edit.), t. 1. fig. 5°; Haldeman, Monogr. 
Limniades, vii. p. 27,t. 4. figg. 19-227; Binney, Land and Freshw. Moll. N. Am. ii. p. 138, 
figg. 222-224°; Sowerby, in Reeve’s Conch. Icon. xx., Planorbis, t. 11. fig. 87°; Clessin, 
in Martini & Chemnitz, Syst. Conch.-Cab. ed. 2, Limneziden, p. 133, t. 21. fig. 1°; Pilsbry, 
Proc. Acad. Phil. 1891, p. 322°. 
Hab. Norta America: from Canada and South of Hudson’s Bay (Moose Factory) to 
Georgia and Yellowstone River 3. 
S. CentraL Mexico, Yautepec, State of Morelos (Heilprin °). 
According to Pilsbry © the Mexican specimens are in every respect typical; but it is 
strange that no other collector should have found it in the much-explored parts of 
Eastern and Central Mexico. 
15. Planorbis fieldi. (Tab. XXI. fig. 6.) 
Planorbis fieldi, Tryon, Proc. Acad. Phil. 1868, p. 281, t. 1. figg. 4,5°; Tate, Am. Journ. Conch. v. 
p. 159 (1870) °; Schmeltz, Catal. Mus. Godeffroy, v. p. 88 (1870)°; Clessin, in Martini & 
Chemnitz, Syst. Conch.-Cab. ed. 2, Limneiden, p. 154, t. 22. fig. 10 *. 
Also with rapidly enlarging whorls, but more inflated and with the left whorl less excavated. 
Hab. S.W. Nicaragua: in pools by the margin of the Lake of Nicaragua, at Granada 
(Tate 2). 
W. Panama (Capt. Field *). 
Clessin* gives Mousson as author and the Samoa Is. as locality for this species: 
probably he was deceived by the fact that P. fieldi is enumerated in the Catalogue of 
the Museum Godeffroy ° (the shells in this museum being chiefly from the Samoa and 
Viti Islands); Nicaragua, however, is there mentioned correctly as the locality for it. 
