1877.] The Ancient and Modern Pueblo Tribes. 591 
would be to the frogs just what that of the axolotl is to Am- 
blystoma. What information the author has given us with the 
description and figures of the single specimen that has come to 
his notice will not allow the assumption that the representative? 
of the genus in Paraguay differ from those in Surinam in respect 
to the length of time passed in the larval stage. It is. well 
known, however, that in other batrachia the metamorphosis can 
be hastened, or retarded, or prevented, as may be desired; that the 
time varies in different seasons and localities according as they 
may be favorable or otherwise; and that in species of a single 
genus, as Rana, the metamorphosis oceupies weeks in some cases, 
years in others. Dr. Jeffries Wyman is said to have kept larve 
of the bull-frog seven years, more than twice the ordinary period 
of existence of the animal in the larval stage. More information 
concerning the species of Pseudis (P. paradoxa, P. minuta, and 
possibly a third for Batrachichthys) is desirable. 
_ A little exercise of imagination enables one to see them grasp- 
ing and swinging from the branches of the plants by means of the 
opposable thumb ; whether this isits use is a question. One can 
imagine the tail and feet both required in the pursuit of rapidly 
moving prey or in escape from lively enemies, but it is only sup- 
position. 
However, we shall wait another chapter in the history before 
accepting Batrachichthys as one of the ‘ missing links ;” the 
reputation of Pseudis as a deceiver is too well established. 
ON THE ANCIENT AND MODERN PUEBLO TRIBES OF 
THE PACIFIC SLOPE OF THE UNITED STATES." 
BY EDWIN A. BARBER. 
E the far Southwest, covering far the greater part of that sec- 
tion of the United States now known as Colorado, Utah, New 
Mexico, and Arizona, and stretching through the great valleys of 
the Rio San Juan and its tributaries, the Colorado and the up- 
per portion of the Rio Grande del Norte, there exist the ruins 
of thousands of stone structures, built by a prehistoric race 
whose individuality has been lost in the obscurity of past ages. 
The great extent of territory which the remains cover, and their 
great number, would indicate a former population of at least 
half a million souls. 
+ Read before the American Association for the Ad t of Science, at Buf- 
falo, 1876, 
