1905. | AMPHIBIANS AND REPTILES. 205 
matinee point to the long-continued land-connection with Eastern 
Asia. A later centre of dispersal lies in the Eastern half 
of North America, the old Appalachia, the Alleghany moun- 
tains, &e., whence Urodeles have spread, as Plethodontine and 
Desmognathine, over most of the Eastern and Southern States, 
also into and through Mexico’s eastern half. This spreading 
dates back to Miocene times, witness the existence of Spelerpes in 
Hayti, while others have reached even South America, and, lastly, 
the occurrence of a Plethodon somewhere in the La Plata basin. 
Much later immigrants, directly from the old north-western home, 
are Amblystoma and Batrachoseps: A. tigrinum and B. attenuatus 
being identical species in the States and in Mexico, only 4. alta- 
mirant being a new modification ; while Spelerpes has developed 
many species, different in the north, centre, south, and in Hayti. 
ANURA, 
PELOBATIDE.—Scaphiopus, the Spadefoot, closely allied to the 
European Pelobates, is the only American genus of this family, 
with about 7 or 8 species, two of which are restricted to the United 
States. The zone of sandy terrain of Texas, New Mexico, and 
California is richest in Spadefeet, whence they have extended over 
the Mexican plateau down to the Pacific and Atlantic coasts. 
S. dugest s.hammondi has the widest distribution: from Missouri 
and California through New Mexico and Texas, the mountains 
west of Chihuahua, in Guanajuato, and again on the southern slope 
of Oaxaca, where I found it at Totolapan, its most southern locality. 
The retiring habits of the Spadefoot no doubt account for the 
few scattered- records. The well-wooded mountain ranges which 
form the south-eastern, southern, and western borders of the 
Mexican plateau are a natural obstacle to a further southward 
spreading of this genus, 
Buronip#.—Central America and Mexico are one of the centres 
of Bufonide. Concerning Mexicans, they can be grouped as 
follows :— 
1. Indigenous: Rhinophryne dorsalis, the only species of the 
genus, a toad specialised as an eater of Termites ; it is restricted to 
the moist Atlantic Tierra Caliente, from Tuxpan, north of Vera 
Cruz, through the Isthmus to Campeche and Guatemala. The 
light- coloured spots on the bluish-slaty black skin are either yellow 
or orange to red, varying in individuals from the same locality. 
They are very sluggish, rather nocturnal, and retire beneath a 
rotten stump or into a small self-dug hole in the moist humus. 
Aztec name “ Poche.” 
2. Southerners : Hngystomops, the few species of which range 
from Venezuela and Ecuador northwards, but only 7. pustulosus 
reaches the Isthmus of Tehuantepec. 
Several of the 13 species of Swfo found in Mexico are southern 
forms: in their spread northwards they either stop short at the 
