PHYSA. 371 
Subvar. plicata. 
Physa mexicana, var. plicata, Fisch. & Crosse, loc. cit. p. 100, t. 30. figg. 11, lla,” (not P. plicata, 
De Kay, 1843). 
Only differing from the type of P. osculans, var. mearicuna, in the longitudinal plaits. 
Long. 17, diam. 10; apert. long. 13, lat. 6 millim. 
Hab. Centra Mexico: near the city of Mexico (Méhédin }*). 
: The plaits are not indicated in the quoted figure 13, the sculpture not being shown 
in this and the other figures of Physa and Aplecta in Fischer and Crosse’s work: in 
the explanation of the figures, fig. 11 is named simply P. mexicana, and fig. 12 
var. plicata, but the quotation in the text (p. 100) and the comparative natural size of 
both prove that the names have been reversed. 
Subvar. tolucensis. 
Physa mexicana, var. tolucensis, Fisch. & Crosse, loc. cit. p. 100, t. 30. figg. 18, 13 a™. 
Only differing from the type of P. osculans, var. mexicana, in its larger size. 
Long. 25, diam. 15; apert. long. 19, lat. 9 millim. 
Hab. Centra Mexico: Toluca (Boucard \4). 
Var. coniformis. (Tab. XX. fig. 17.) 
Physa ventricosa, Uhde, MS. in Mus. Berol.”. 
Physa osculans (Haldem.), v. Mart. Malak. Blatt. xii. p. 58 (1865). 
Physa mexicana, var. coniformis, Strebel, Beitr. Mex. Land- und Siissw.-Conch. i. p. 52, t. 6. 
fig. 269". 
Physa osculans, var. patzcuarensis, Pilsbry, Proc. Acad. Phil. 1891, p. 323, t. 15. fig. 5. 
Last whorl swollen above, and from thence gradually narrowing downwards. Shell rather thin, some 
specimens with malleated impressions. 
Long. 18, diam. 11; apert. long. 14, lat. 7 millim. 
Hab. Centra Mexico: Patzcuaro, State of Michoacan (Uhde 1°", Heilprin 38). 
This form has somewhat the appearance of a young shell, but it seems to be confined 
to one lake, and young specimens of var. mexicana have a quite different shape. 
Var. boucardi. (Tab. XX. fig. 18.) 
Physa mexicana (part.), Strebel, loc. cit. p. 51, t. 6. figg. 26 a, e”, 
Physa boucardi, Crosse & Fisch. Journ. de Conch. xxix. p. 334 (1881)*; Miss. Scient. Mex., 
Mollusca, ii. p. 102, t. 30. figg. 4, 4a”. 
More elongate, aperture distinctly narrower, elliptical, its external margin less arcuate than in the true 
P. osculans. 
a. Long. 21, diam. 13; apert. long. 15, lat. 7 millim. 
b. as 163, ” 9; ” ll, ,, 53 ” 
C. 9 11, cr) 6; ” 73, ” 34 ” 
a. Crosse and Fischer’s statement” *'; 6, c. Strebel”. 
Hab. CENTRAL Mexico: Lake of Mexico (Boucard © 1); city of Mexico (Strebel 19), 
47* 
