district exliibits all the characteristics of the Austro-riparian 

 region, lacking, however, to some extent, those of Texas and 

 Florida. The entire reptilian fauna of the State may be said 

 to be reprcsetitedby about 114 species, belonging to 56 genera; 

 representing 25 families in 8 orders. It is possible, hoAvever, 

 that this list may be considerably augmented by species 

 which are, so far, supposed to be confined to the Florida and 

 Texas districts. In general, the enumeration may be ac- 

 cepted as adequately correct, for the species of this class are, 

 more or less, confined to their native localities, as migration, 

 in the stricter acceptation of the term, can scarcely be 

 ascribed to any reptile. Aquatic forms may gain considerable 

 distribution by means of their element, but beyond that they 

 would encounter obstacles over which wings only could trans- 

 port them. On the other hand, terrestrial forms would be 

 even more eifectually checked in their attempts to extend 

 their original habitat. It is true, however, that a certain 

 species may occur in localities which are separated by ap- 

 X^arently insurmountable obstacles, and we can only account 

 for such an instance by the supposition that at one time 

 or other such barriers did not exist. 



Certain localities of our state are marked either by an en- 

 tire absence, or a greater abundance of forms. The southern 

 section i^resents marked features in this respect in aquatic 

 types of Ophidians. Here, also, the alligators are present 

 in greater numbers, while the Testudinata, in general, are al- 

 most entirely confined to Southern Louisiana. The hilly 

 parts, the pine-flats and xnne-hi lis have each their peculiar 

 representatives. The majority of the Lacertilia, the only Pro- 

 teroglyph, as well as all Soleuoglyph snakes, with one excep- 

 tion, are found in far the greater number in upper Louisiana. 

 Isolated and prominent in these respects stands Avery Island 

 [Petit Ause] as a kind of haven for almost the entire reptile 

 world of the state. Surrounded by immense tracts of marshes 

 and swamps, in themselves a congenial habitat for the more 

 or less aquatic types, this hilly, forest-covered island har- 

 bors almost all the more terrestrial forms. In fact, this 

 comparatively small area is an ideal paradise for the or- 

 nithologist as well as the herpetologist. Comparing the nat- 

 ural topography of upper Louisiana and its identic forms, 

 with this small island on the extreme southwestern coast, 

 and considering [for some reptiles] the almost insurmountable 

 regions which intervene, we have an illustration of such 

 a distribution, which we can only exi)lain by a formerly uon- . 

 existing seiiaration of the two localities. 



