208 DR, H, GADOW ON MEXICAN [June 6, 
shrubs at the edge of a forest, were quite green, but they soon 
changed to reddish yellow and ultimately assumed the normal 
reddish colour. 
Of the 5 species of Leptodactylus, 3 are too little known, 
L. microtis from “‘ Guanajuato ” would be the only instance of the 
occurrence of a Leptodactylus on the plateau instead of in the 
lowlands. Only two species have a wide distribution : L. albilabris 
of South Guerrero, Oaxaca, and of Vera Cruz, also Antillean ; 
L. caliginosus from Paraguay northwards, in Mexico in the 
‘Pacific Tierra Caliente as far as Mazatlan. 
ENGYSTOMATID, with an obviously South-American centre of 
dispersal; not Antillean. The small genus Hngystoma reaches 
through Mexico into the South-eastern United States (1. wstwm). 
Ranww#.—This family is essentially Paleo-tropical. Scarcely 
more than a dozen species, all belonging to Rana, occur in North 
America, only 6 in Mexico, and fewer still further south, in 
the north-western portion of South America. There, however, 
the Ranide have found a new congenial home, which has stimulated 
them into the development of 5 new genera, with about one dozen 
species, all arboreal, besides Dendrobates. The Ranide have not 
found their way into the Antilles. 
Of the six Mexican species, 2. forreri is restricted to the district 
between Durango and Mazatlan; 2. pustulosa to same district 
and Western Jalisco; &. omiltemana to Guerrero mountains: 
these three are peculiar to Mexico. &. halecina is the common 
river-frog of the country, both in the hot parts and on the plateau, 
extending from the United States through the whole of Mexico 
down to Costa Rica.  palmipes ranges from southern tropical 
Mexico to South America. Lastly, 2. montezwme, the largest of 
all, is a lake-dweller, e. g. lakes of Jalisco, near Mexico City, 
Tehuantepec, extending south into Tabasco and Guatemala. 
Résumé of the Distribution of Mexican Anura. 
We can easily distinguish between northern and southern 
immigrants. 
1. Northern, decidedly of Nearctic origin. Scaphiopus, scarcely 
reaching the Isthmus of Tehuantepec; and a few Rana, all water- 
frogs. Both genera are comparatively recent immigrants, non- 
Antillean, although Rana extends through and beyond Central 
America. 
2. Southern, of obvious South-American origin.—a. With 
related, or identical, species in the Greater Antilles. Cyséz- 
gnathide, not reaching the United States. Wylide and Bufonide, 
each, especially the Hylide, with genera peculiar to Mexico, 
indicating ancient residence.—b. Non-Antillean, a few Hngysto- 
matine, scattered through Mexico, 
