1897,] A Chapter in the History of Science. 841 
He also found that the characters so revealed served to fix the 
places in the system of the groups in question. In their early 
stages the Firmisternials (or frogs and their relations) have the 
shoulder-girdle moveable, and thus resemble the Arcifers 
(toads, ete.), which have the opposite halves movable during 
their whole life time; thus it became evident that the latter 
are the lowest or most generalized forms, and the former more 
advanced and higher in the system. The development of 
teeth, which had been supposed by the earlier systematists to 
be of paramount value, and which Cope, following in their 
footsteps, had also originally unduly valued, has been found 
to be of quite subordinate importance. 
The lizards were also in former times distributed into fami- 
lies and other groups on account of variations in superficial 
or external characters, such as the form of the tongue, the ar- 
rangement of the scales and the development of legs and feet. 
Cope dissected examples of all the types he could obtain and 
found that such superficial characters were often misleading, 
and he proceeded to arrange them with reference to the pre- 
_ponderance of all characters. The structure of the cranium 
especially was analyzed, and the variations and concordances 
in the development of various bones were tabulated. These 
characters were supplemented by others derived from the ver- 
tebree, the shoulder girdle, the teeth, the tongue and the pho- 
lidosis. Familiarity with his subject enabled him almost in- 
stinctively to assess the relative values of the different charac- 
ters, and he obtained fitting equations which resulted ina 
system which has received the approbation of the most compe- 
tent judges to the present time. 
The extent of Cope’s influence on herpetology may be to 
some extent inferred from the catalogues of the richest collec- 
tion of reptiles and amphibians in existence—the British 
Museum’s. Descriptive catalogues of both the Anurans and 
Saurians have been published at different times. In the early 
catalogues are adopted the views current at the dates of pub- 
lication-—1845 for the lizards ; 1858 for the batrachians, New 
editions were published many years later and the systems of 
Cope were adopted with slight modifications. In his catalogue 
