Ranina. 



347 



Both the series of Opiathoglosga arc not to be considered a> form- 

 bag one continued series between the Agloaaa and ProterogloMa ; 

 they (!n not form one aeries of animal-, descending from tin- mosi 

 highly organized form to the lowest one i such a gradation i- equally 

 found in both series; and one is at once struck with the identity of 

 the chararacters in the single families, if brought Bide by side in two 

 parallel series. 



OPISTIIOGLOSSA. 



OxYDACTYLA. Pl.ATYD A( TV I. \ . 



Ranidee. Polypcdatidx. 



Cystignathida;. Hylodidsfe. 



Discoglossiikc. Hylidse. 



AaterophrydidsB. ..'. ► Hylina, 



I'peroliiilic Phyllomedusids, 



Alytidae. Pelodryadidrc. ) 



Bombinatorina. Bombinatorida:. Micrhylidac. Micrlivlina. 



'^^MESL.. :::::::::::: 



| Rhinodcrmatidae. Hylsdactylidae. | 



n..c • Engystomatida\ Brachvmerida:. Hi i • 



Bufon.na. Bufonidas. .'.... , Hylapleuna. 



I llylaplcsidtc. 



I am always afraid of admitting teleological principles into natural 

 science ; the most important results of truth are gained by adhering 

 to objective facts, and by inquiring into them. Each system should 

 be adapted only to the present state of our knowledge of animals ; but 

 at last we must come to that point where analogies will enable us to 

 look further, and the future will show (if it is allowed to presume 

 so far) that, among the forms which hereafter may be discovered, 

 there will be found correspondents to the Asterophrydidce, Phry- 

 nisiiihe, Brachycrphalidce, Bufonidee, and Hylaplesidee, viz. : — 



1. Ilijlina, without paratoids, with dilated sacral vertebra and free 



toes. 



2. 0. platydactyla, without maxillary teeth and with imperfectly 



developed car. 



3. Bufonina, without paratoids, with not dilated sacral vertebra 



and webbed toes. 



4. Hylaplesina, with paratoids, with dilated sacral vertebra, and 



webbed toes, 

 (/nly three genera are known belonging to the first gronp of 

 Anura, to the Aglossa, — Dactylethra, Pipa and Myobatrachiu, the 

 latter of which is imperfectly known to myself from a Bhorl not;. 

 Dr. Gray in the ' Proc. Zool. Soc.' All these three genera offer Buch 

 characters as to become the types of as many families. But a- I do not 



know whether the Mar-like configuration of the toes in Pipa, or the 



horny claws of the toes of Dactylethra, have the same functional im- 

 portance a- in the Oxydaetyla and Platydactyla, or whether the 

 two horizontal fangs in the intermaxillary bone of Myobratrachx 



true teeth, or only apophyses (a- in the lower jaw of 



1 am at alosswhich of the8e character.- mn-t he -uhoidinatcd to tin 



