18 



Axolotes, Oweu, 1844, 101, xiv, 23. 



Vomero-palatiue teeth in a nearly straight, sometimes interrupted, 

 row behind the choanse. Tongue broad, free margin narrow, the upper 

 surface with numerous narrow folds. Tail usually somewhat compressed. 



As formerly defined, this genus would comprise about eighteen species. 

 As defined by Professor Cope, it will contain still about thirteen species. 

 Of these we certainly have in Indiana six, and possibly more. 



The Ambystomas are familiarly known as "Mud-puppies," and are 

 frequently met with in the operations of plowing, digging ditches and 

 cleaning out cellars. They are often not distinguished from lizards, but 

 the latter are very active, while the former are extremely slow in most 

 of their movements. The Ambystomas, like all similar animals, are 

 regarded as venomous and are usually destroyed on sight. On the con- 

 trary, they are the most innocent animals imaginable. They can not be 

 provoked to bite ; and if they should do so, they have no poison glands 

 connected with their teeth, and the teeth are so very short that they 

 could scarcely penetrate the skin. 



The species appear to be mostly nocturnal in their habits. Their food 

 in the adult stage consists of insects, small mollusks, and more especially 

 of earthworms. Their winters seem to be spent near the borders of 

 ponds, and in these, as soon as the ice is broken up in the spring, their 

 eggs are deposited. These are surrounded by a mass of gelatine, by 

 means of which they cling to one another and to grass and sticks. The 

 tadpoles are slenderer than are those of toads and frogs, and they have 

 branching external gills. They look a good deal like small catfishes In 

 due time these tadpoles lose their gills and betake themselves to the land. 

 The larvse of some of the species attain a large size before undergoing 

 their metamorphosis, and one species has been known to breed while still 

 possessing gills. 



Key to the N. A. Species of Ambystoma.^ 



A. Tongue with a median crease from which the papillary folds di- 

 verge in a pinnate manner. Palatine teeth not extending be- 

 yond the choanae. microsiomum, p. 19. 



AA. Tongue with the papillary folds radiating from a point at the back 

 of the tongue. Palatine teeth extending laterally beyond the 

 choanse. 



=''In determining the species of Ambystoma great care should be exercised. Too much 

 reliance must not be placed on this key, but the descriptions must be appealed to, and the 

 animal in hand carefully compared' with them. Those costal grooves are to be counted 

 which plainly lie between the fore and the hind legs. The number of these, in any species. 

 may occasionally be one more or less than here given. Examine both sides of the body, 

 The color and character of the spots may vary within limits. 



