62 Zoological Society ; — 



A. Aglossa : B. a. without tongue. 



B. Opisthoylossa : B. a. with a tongue adherent in front, and 

 more or less free behind. 



C. Proteroglossa : B. a. with a tongue free in front and adherent 

 behind. 



We find by far the greatest development and the greatest variety 

 of forms in the second group ; and therefore I prefer to consider the 

 principles of further division first in this group, hoping to obtain in 

 this way points of view^ according to which we may characterize and 

 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. The 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, the tongue serves this pur- 

 pose. 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 filhping it out of the mouth as the frogs, or 

 only turning it out, as the toads do, with broad and fixed tongue : 

 the mechanism of seizing is the same as in Myrmecophaga, Picus, or 

 Chameleon. On examining the recently swallowed animals from the 

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

 lacerated condition ; whilst those taken from the stomach of a 

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

 even the case with Ceratophrys 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 in some of the 

 species there are 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 with 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 Dasypus gigas, which exhibits more teeth than any 

 other mammal except some Cetacea. So also the Salmonidee contain 

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

 What influence the dilated or more cylindrical form of the process 



