. MOLLUSCA. 643 
To the localities given, add :— 
Hab. Crentrau Costa Rica: Virilla, Torres, Maria Aguilar, and Tiribi, in all rivers 
_ and streams, and during the rainy season in ponds near them (Biolley}*); La 
Uruca, near San José, in an irrigation stream (“rigole”) running through muddy 
ground, 1100 metres (Biolley). 
Physa fuliginea (p. 360). 
To the localities given, add :— 
Hab. Crentrau Costa Rica: Rio Torres, near San José, on stones, in a strong current 
(Biolley) ; Pila de Los Angelos, Cartago, 1400 metres (Biolley: typical form and 
var. pliculosa). 
Physa spiculata (p. 366). 
To the localities given, add :— 
Hab. §8.W. Costa Rica: Diquis, below Terraba, 100 metres (Pittier). 
Var. tapanensis (p. 367). 
Aplexa tapanensis, Pilsbry, Nautilus, xiii. p. 189”. 
Hab. S.K. Mexico: San Juan Bautista in Tabasco (Rovirosa !°). 
CrntraL Costa Rica: La Uruca, near San José, in an irrigation stream running 
through muddy ground, 1100 metres (Biolley). 
Physa osculans (p. 370). 
According to Stearns | Proc. U.S. Nat. Mus. xiv. p. 104 (1891)], the typical form of 
this species occurs as far north as the United States bank of the Rio Grande; it 
therefore probably inhabits N.E. Mexico. 
Var. mexicana (p. 370). 
To the localities given, add :— 
Hab. |N. Centrat MExico :| Lake Palomas, in the Mimbres Valley, State of Chihuahua 
[International Boundary Commission: see Dall, Proc. U.S. Nat. Mus. xix. p. 369 
(1896)]. Also found at various places in New Mexico, Arizona, and California, 
according to Dall (loc. cit.). 
Var. rhyssa. 
Physa osculans, var. rhyssa, Pilsbry, Proc. Acad. Phil. 1899, p. 401 aan 
Smaller than typical osculans, with numerous slight longitudinal folds on the last whorl. 
Hab. N.E. Mexico: Saltillo, State of Coahuila (Ir. & Mrs. Rhoads **). 
N. Cenrrat Mexico: Lake Palomas, in the Mimbres Valley [International Boundary 
Commission: see Dall, Proc. U.S. Nat. Mus. xix. p. 368 (1896)]. 
LIMN ZA (p. 376). 
The genus Limnea is also found in Costa Rica, P. Biolley having sent me a specimen 
from Rio Torres, near San José, but I dare not venture to determine the species. 
81* 
