2 
MR. W. K. PARKER ON THE STRUCTURE AND 
characters as are easily seen by the Zoologist is to build upon a sanely foundation ; none 
will be more ready to acknowledge this than those who are most familiar with the group. 
Even the cranial characters, which lie deeper down, are extremely variable, so that 
in formulating them for any division or sub-division of the Order it is always necessary 
to give some qualification of the scheme, and to say that “as a rule ” such and such 
modifications of structure exist in the group under notice. 
Our “genera” suffer from this weakness; and in some cases, notably in the great 
genus Rana, there are morphological modifications and variations such as are not to be 
seen in whole groups of Families in the Osseous Fishes. 
On the whole, my own views correspond very accurately with those of my friends 
Messrs. Gunther, Mivart, and Wallace (whose works are referred to in the biblio¬ 
graphical list); they, I am satisfied, will be struck with the evidence here shown of 
the common origin of groups of the Batrachia that now are very widely dispersed, and 
marked by every variety of external character. 
For there can be no doubt that these curious fishy air-breathers are, as Mr. Wallace 
has suggested to me, a very ancient kind of Vertebrates. They have not struggled 
for life through one but through many epochs; they have been put to every kind of 
shift to live, and with infinite readiness and adaptability they have become all things 
to all conditions. 
Here, undoubtedly, we get light upon the mystery of the great perfection of the 
various organs seen in the members of so lowly a group ; for they are mere anamniotics 
at the best, and their upspring has been from some of the lowest of the Vertebrate 
stocks. 
In every kind of facility for motion, in organs of sense wonderfully perfect, in power 
of speech and of song, and in instincts and habits innumerable, the Frogs and Toads 
teach the order, and anticipate the life of the peopled kingdoms of the nobler tribes 
that have risen above them in the scale. 
The Salamandrian tribes (“ Urodela”) have branched up and beyond the “ Dipnoi” 
( Lepidosiren , Ceratodus), and more or less, as a rule, lose them gills after a time, 
acquiring, in each type, a fenestral passage and a stapedial plug to their ear-capsule. 
They also, in harmony with their more and more terrestrial habits, acquire a 
rudimentary larynx, so that the beginnings of the better kinds of organs of hearing 
and of voice are found in them. 
But the Batrachians, springing from another part of the “ stock,” and indeed from 
a far lower “ node,” rise high above the Salamandrians in the metamorphosis of their 
organs, especially those of voice and hearing; their general intelligence and their 
gymnastic powers are also of a much higher kind. 
Supposing the Urodeles to have arisen from some archaic forms of the “ Dipnoi,” 
the height in the scale of such double-breathing Fishes must have corresponded very 
closely with the Crossopterygii, and these again are manifestly a mere subdivision of 
the great “ Ganoid ” order. 
