4 
NORTH AMERICAN BATRACHIA AND REPTILIA. 
indebted to tlie Northwestern University, and to the Chicago 
Academy of Sciences, for free access to their museums and 
libraries. They also feel under especial obligation for assistance 
of various kinds to Professors S. A. Forbes, Oliver Marcy, S. F. 
Baird, Mr. R. E. Earll, D. S. Jordan, and Doctors J. W. Velie 
and P. R. Hoy. In those instances in which the distribution of 
species has been extended beyond that given in Prof. Cope’s 
check list, the new locality is noted in italics. Preceding the 
glossary which is appended to the catalogue, will be found a 
description of the faunal regions of the United States, as limited 
by Prof. Cope. 
SYNOPSIS OF CLASSES. 
Mammary glands absent; blood cold; not less than two 
aortic arches; no fin rays. 
a. Respiration through whole or part of life effected by 
means of branchiae; lungs present in adult; two occipital con- 
dyles; no thoracic diaphragm; usually no scales or scutes, when 
present they are imbedded in skin; limbs, when present, well 
developed, with two or more digits; heart trilocular; no sternal 
ribs; undergo metamorphosis after leaving egg Batrachia. 
b. Respiration never effected by means of branchiae, but 
after birth performed by lungs ; no separate parasphenoid; a sin- 
gle convex occipital condyle; sometimes an incomplete thoracic 
diaphragm; body usually covered with scales or bony plates; 
metatarsal bones not ancliylosed together or with distal tarsal 
bones; venous and arterial currents of blood mingled either in 
the heart itself, or at the origin of the aortic arches; undergo no 
metamorphosis after leaving egg Reptilia. 
