341 



show tin' same peculiarity. In fact, this osteological form teems to 

 be connected with none of the modifications of locomotion ; for ue 



Hud among these Batrachians good swimmers as well as bad, tree- as 



well as earth-frogs, those which always hop as well a- those which 



often crawl ; finally we are unable to refer to it a peculiarity of any 



part of the propagation. Generally, I can only state — 



1. That all the Batrachia anura without maxillary teeth exhibit 

 dilated jnocesses of tin- sacral vertebral, except the Bylaplesidae ; 



hut that, on the other hand, the Batrachia anura with maxillary 

 teeth may have this bone sometimes dilated, and sometimes cylin- 

 drical in form. 



2. That all the Batrachia anura with paratoids exhibit diluted 

 processes (without any exception at present) ; hut that, on the other 

 hand, the Butrachia anura without paratoids have either this bone 

 dilated or cylindrical in form. 



From the above inquiries it is evident that I do not think this 

 anatomical character fit for separating the whole group of the Opis- 

 thoglossa, so as to form two natural divisions ; and there remains onh 

 the third of the above-mentioned characters, — the dilated or not ili- 

 lated lip of the fingers and toes. 



This natural character is connected with a strongly marked di- 

 stinction in the mode of life, with climbing trees, which peculiarity 

 IS justly considered as one of the most important characters among 

 the Vertebrata. No frog or toad without dilated toes is known to 

 climb trees; and although our knowledge of the mode of life of 

 the tropical forms is very limited, I have no doubt that the tooth- 

 less Batrachians with dilated toes, of the tropics (Hi/lajjlcsia, Hy~ 

 tedactylus, Brachymervs, &c), are enabled to climb trees, walls, 

 &C., some being active during the day, others during the night. 

 I am well aware that there are forms having the toes so slightly di- 

 lated that it is difficult to say to which part they belong; but in 

 Bucb instances the question will be decided either by observation of 

 the living animals or by the more distinguishable form of closely 

 allied species, as tor example in the genus Hylodes. The objection 

 to separate in this way the toothless Batrachians, which it was till 

 now the custom to consider as a natural one, I icet o\er by the fact 

 that my two proposed series arc parallel, and their members nearly 

 corresponding ; and 1 trust that at a not far distant time some of the 

 wanting forms will he found. Therefore I divide the .liiuru >pixthu- 



!/fossa into two series : — 



1. Opisthoglossa oxydaetyla: Opisthoylossa with cylindrical or 

 pointed tip of the fingers and toes. 



2, Opisthoglossa platydactyla ■ Opisthoglossa with dilated tip of 

 the fingers and toes. 



Among the animals of both series we find that the >ame characters 



recur ; ami SO we are enabled to apply in both Belies the smir fur- 

 ther division. I have already mentioned what value I am disposed 



to attribute to the dentition ; and by co-ordinating with it the' >t i m 

 lure of the ear, I think we ma\ obtain natural and -ciciitilicalU 



