1869.] MR. ST. GEORGE MIVART ON ANUROUS BATRACHIANS. 281 
it adopts from the labours of Mr. Cope osteological characters noticed 
by him, but which are here restricted in their application to the 
limitation of more subordinate groups than those tor which he uses 
them. 
Mr. Cope’s osteological system would divide the Anura into two 
great series, the Arciformia and the Raniformia. 
The Raniformia are thus characterized * :—*‘ Coracoidei abutting ; 
epicoracoidei, when present, continuous, transverse, and abutting on 
coracoidei ; not connected with the latter by overlapping longitudinal 
cartilages.” 
The Arciformia are distinguished as follows + :—‘ Acromials and 
coracoids divergent, the former directed forward and connected with 
the latter by a longitudinal arched cartilage, which is free from, and 
overlapped by, the corresponding cartilaginous arch of the opposite 
side.” 
This system associates Bombinator, Pelodytes, and Cultripes with 
Hyla, Cystignathus, Hylodes, and Bufo, in one division; while 
Engystoma, Phryniscus, and Hemisus are altogether separated from 
the trne Toads, in order to be classed with Rana, Hylarana, &c. 
Such approximations seem to me forced and unnatural, and likely 
to lead to the rejection of the system from which they necessarily 
result. 
Mr. Cope employs other osteological characters for more subor- 
dinate groups; thus his Hylidet are characterized, among other 
points, as having the ‘‘ fronto-parietalia shortened anteriorly, usually 
embracing a fontanelle,’’ and ‘‘superior plate of ethmoid never 
covered by fronto-parietals, usually produced anteriorly, between 
fronto-nasals.”’ 
Skeletal characters are, indeed, most valuable ones in leading us to 
detect the deepest and truest affinities of vertebrate animals. But 
these affinities once found, it is very desirable that zoological classi- 
fications should not, if it can possibly be avoided, repose upon them 
only, but rather on more externa] and more readily ascertainable 
characters. Such external characters will probably be found to 
exist in all really natural groups, although they may turn out to 
be distinctions so little obvious that they might never have been 
noticed, but for the guidance afforded by the previous careful study 
of the osteology of such groups. 
As to the particular character selected to distinguish Mr. Cope’s 
two great primary divisions, I cannot think it of anything like the 
importance § he attaches to it. The point is one easily to be studied, 
as the Common Frog is the type of the Raniformia, while the Com- 
mon Toad exemplifies the Arciform type of structure. 
When the two adult shoulder-girdles are compared, a considerable 
* Journal Acad. Phil. new series, vol. vi. pt. 2, p. 190. 
t Ibid. pt. 1, p. 67. 
{ Ibid. p. 83. 
§ Lam fortified in this, I rejoice to say, by the valuable opinion of one of the 
very first of existing osteologists, I mean my esteemed friend Mr. W. K. Parker, 
E.R.S. 
