642 SUPPLEMENT. 
15. Succinea tlalpamensis. 
Succinea tlalpamensis, Pilsbry, Proc. Acad. Phil. 1899, p. 401°. 
Allied to S. retusa, Lea, and S. salleana, Pfr.; aperture decidedly larger than in the former, and spire longer 
and more slender than in the latter. 
Long. 143-15, diam. 8-83, apert. 11-8-12 millim. 
Hab. Centrat Mexico: Tlalpam (Mr. & Mrs. Rhoads'). 
Var. cuitseana. 
Succinea tlalpamensis, var. cuitseana, Pilsbry, loc. cit. p. 401 *. 
A smaller form. 
Long. 9°6—10°8 millim. 
Hab. Centrat Mexico: Lake Cuitseo, near Huango, State of Michoacan (Ir. & Mrs. 
Rhoads ). 
XANTHONYX and CRYPTOSTRACON (pp. 343, 344). 
Notes on the anatomy and affinities of these two genera are given by Pilsbry and 
Vanatta (Proc. Acad. Phil. 1898, pp. 229, 230), and Pilsbry (Proc. Malac. Soc. Lond. 
iv. pp. 27-30, t. 3. figg. 12-15). 
METOSTRACON. 
Metostracon, Pilsbry, Proc. Malac. Soc. Lond. iv. p. 24 (March 1900). 
This new genus is described as slug-like, with the shell flat, spiral, and covered by 
the mantle. 
1. Metostracon mima. 
Metostracon mima, Pilsbry, loc. cit. p. 27, t. 3. figg. 1-11’. 
Hab. Centran Mexico: Morelia and Uruapam, State of Michoacan (Rhoads 1). 
CARYCHIUM (p. 352). 
Carychium exiguum, var. mexicanum (p. 352). 
To the localities given, add :— 
Hab. [E. Mexico:| San Juan Miahuatlan, State of Vera Cruz, found within Eucalodium 
cereum (coll. Strebel, in Mus. Hamburg.). 
PHYSA (p. 353). 
Physa aurantia (p. 356). 
Pilsbry (Nautilus, xiii. p. 139) mentions this species as found by Prof. Rovirosa at 
Macajuca, apparently in Tabasco. Perhaps it was P. impluviata 2 
Physa impluviata (p. 358). 
Physa aurantia {part.), Biolley, Mol. terr. y fluv. de Costa Rica, p. 17%. 
