1885.] Geology and Paleontology. 593 
from Leybach in the museum of Princeton College, New Jersey. 
As they agree exactly with Dr. Fritsch’s figures of Archegosau- 
rus, it is difficult to perceive why he denies the accuracy of my 
statement in the matter (p. 15). 
Both the authors here reviewed have evidently been more or 
his. characters in defining his genera. We cannot but think that 
the publication of this system was a misfortune to the progress of 
the subject. The characters of the relative position of the 
eyes and nostrils and the outline of the skull are certainly only 
specific characters, and the veriest tyro in the study of recent 
Batrachia would not use them for generic characters, still less for 
family characters, as is done by Mr. Miall 
ydekker’s paper introduces an undoubted member of the 
order Rhachitomi to the Indian Permian fauna, and devotes his 
usual care to the description and illustration of it. Unfortunately 
the skull of the single specimen at his disposal has lost the bones 
of its superior face, so that many of the characters of the species 
given the barbarous name Gwandanosaurus, is not so defined as 
to be distinguishable from some of those already known. In 
view of its possibly turning out to be identical with some of 
these, Dr. Lydekker remarks that he relies on the spirit of the 
following rule of the International Nae en Congress of Bologna 
“in favor of his own name,” z.¢., “In future for specific names 
priority shall not be irrevocably reh unless the species shall 
ave been not only described but figured.” This is a doctrine 
ing illustrations unnecessary, are much more inportant than they 
to the real advancement of science. 
Examples of the disregard of the law of priority in this paper 
are seen in the proposition that the name Actinodontide super- 
sede Eryopidæ of prior date, and the use of the term hypocen- 
trum for intercentrum of prior date. This we hold to be simply 
creating confusion, and causing much inconvenience to the stu- 
dent! Moreover, Dr. Lydekker has not read the paper which 
he quotes. He states (p. 7) that the intercentrum of Cope is the 
pleurocentrum of Gaudry, and the centrum of Cope is the hypo- 
centrum of Gaudry. The fact is the reverse. The intercentrum 
was renamed hypocentrum by Gaudry, and the centrum of Cope 
1 The same untenable method is evinced in Dr. Lydekker’s mnl of the name 
Creodonta ( wet Lege the proposition to use in its stead the inconvenient expression 
“Carnivora primigenia” (Catalogue of Fossil Mammalia in British Museum, 1885, 
p. 20). 
