340 



divide the few known forms of the other groups. Those characters 

 which are generally considered as the most important, and which 

 always command a separation of two Batrachians, are : — 



1 . The presence or absence of the maxillary teeth. 



2. The dilated or cylindrical form of the transverse process or dia- 

 pophysis of the sacral vertebra. 



3. Tbe dilated or not dilated tips of the fingers and toes. 

 When we consider that the lower jaw of the tailed Batrachians is 



provided with a series of teeth, and that these are wanting in the same 

 bone of all the tailless Batrachians, we are obliged to acknowledge 

 the importance of this character, — the more so as this difference is 

 followed by a difference in the mode of life, as far as I have been 

 enabled to observe it in European forms. In the former the teeth 

 are the organs for seizing the food ; in the latter, as well in those 

 with maxillary teeth as in the toothless, it is the tongue. The 

 former seize the prey in the same way as the Saurians do, and hold 

 and press it with the teeth ; the latter seize it with the clammy 

 tongue, either filliping it out of the mouth as the frogs, or only turn- 

 ing it out, as the toads do, with broad and fixed tongue : the mecha- 

 nism of seizing is the same as in Myrmecophaga, Picus, or Chamce- 

 leon. On examining the recently swallowed animals out of the sto- 

 mach of a lizard or newt, we shall find them always in a more or less 

 dilacerated condition ; whilst those taken from the stomach of a 

 toothed or toothless frog or toad are constantly uninjured. This is 

 even the case with Ceratoplirys and Cystignathus, which are provided 

 with the strongest dentition among all the Batrachians. The prey 

 when seized is held and pressed by the tongue against the upper 

 part of the cavity of the mouth ; and though there are in a part 

 of the species maxillary teeth, they appear to be entirely without 

 function, and palatine teeth alone give assistance to this second part 

 of the action. Therefore, not being able to consider the character 

 of the dentition among the tailless Batrachians as one intimately con- 

 nected with their mode of life, I think it right to subordinate it to 

 another character which does correspond to this pretension. In a 

 similar way the value of dentition is disregarded in the Edentata, 

 which contain the toothless Myrmecophaga and Manis, and on the 

 other hand the Dasyjms gigas, which exhibits more teeth than any 

 other mammal except some Cetacea. So also the Salrnonidse contain 

 the nearly toothless Coregoni and the strongly-armed Sulmones, &c. 

 What influence the dilated or more cylindrical form of the process 

 of sacral vertebra has upon the mode of life is difficult to explain, 

 as it does not absolutely correspond with other physiological or ana- 

 tomical characters. The pelvis obtains by the dilatation of these 

 processes much more firmness ; and a lateral motion is more or less 

 entirely impeded. We should therefore expect to meet with this 

 character in those Batrachians which are provided with the longest 

 and most powerful hind legs, according to the physical problem, 

 that the longest lever requires the strongest centre. But on the 

 contrary, the Batrachians with the shortest legs exhibit a much-dilated 

 sacral vertebra, whilst on the otbor hand the long-legged Hylida 



