CHAPTER IX. 
FROGS. 
HERE are about a thousand different kinds of Frogs and 
Toads, of which by far the greater number, namely, 
the Phaneroglossa, are divided, owing to the formation of 
the pectoral arch (the construction of which need not be described 
here), into the two series, (1) J%rmisternia and (2) Arcifera. 
Toads belong to the latter series. The F%rmisternia are arranged 
in four and the Arcifera in eight families. 
Of the Firmisternia, the Ranide is the first and by far the 
largest and most important family, numbering eighteen genera, 
and something like 245 species. The Ranidw may be described 
as true Frogs. ‘‘It is probable,” says Mr. St. George Mivart, 
‘*that no other existing animal is more replete with scientific 
interest of the highest kind than is the Frog.’”’ Owing to the 
sufferings it has endured in the cause of science, it is well called 
the ‘‘ Martyr of Science.” 
A few matters of interest in regard to the Frog may be referred 
to here in the following brief fashion : 
(1) The legs (the hind limbs) of a Frog have each four 
segments, instead of three, as in man and in most mammals, 
birds, and limb-bearing Reptiles. 
(2) Behind the eye there is a rounded surface of ‘‘smooth, 
tightly-stretched skin” called the ‘‘tympanum,”’ which covers 
the drum of the ear. 
