314 GEOGRAPHICAL AXD GEOLOGICAL DISTRIBUTION". 



Belgium. Cistudo lutaria and Testudo Graeca, the latter intro- 

 duced, inhabit the waters of Southern France; the first of these 

 also inhabits Switzerland, but it is only doubtfully indigenous to 

 that country. The number of species occurring in North America 

 north of the Mexican boundary is about forty, nearly one-half 

 of which properly belong to the Southern United States. Among 

 the commoner or better known forms are the box-turtles (Cistudo, 

 Cinosternum), wood-turtles (Chelopus), painted-turtles (Chrysemys), 

 marsh -turtles (Malacoclemmys), terrapins (Pseudemys), musk-turtles 

 (Aromochelys), snappers (Chelydra), and soft-shells (Aspidonectes), 

 all of which are very broadly distributed, especially in the Eastern 

 and Southern United States. The species having the most ex- 

 tended range is the common snapper (Chelydra serpentina), which 

 is found from Canada to Ecuador. Two other species, the common 

 wood-turtle (Chelopus insculptus) and the painted-turtle (.Chrysemys 

 picta), range as far north as Canada. 



Most of the species of Chelonia are restricted to a single faunal 

 region, and where identical species are found in more than one 

 continent, the range of the species on the continent not properly its 

 home is, as a rule, very limited. Two species are known to be 

 common to Europe and (North) Africa Testudo nemoralis and 

 Cistudo lutaria (C. EuropaBa); one species, Pyxis arachnoides, is 

 common to the continent of Africa (with Madagascar, and some of 

 the neighbouring islands) and India; and likewise one, Manauria 

 fusca, common to the East Indies (Java, &c.) and Australia. Tur- 

 tles are wanting in the true oceanic islands, but they are sufficiently 

 abundant in many of the continental islands, even where these are 

 distant several hundred miles from the nearest mainland. Two of 

 the most ponderous representatives of the order belong to such isl- 

 and groups : the Galapagos turtle (Testudo nigra) and the elephant 

 turtle (T. elephantina), the latter, whose weight is known to reach 

 five hundred pounds, inhabiting the Seychelles and some of minor 

 island groups of the Mozambique Channel. 



Of the four more generally recognised families of land and 

 fresh- water turtles, the Testudinidae, Emydse, Chelydae, and Triony- 

 chida3, only the first has representatives in all the major divisions 

 of the earth's surface. Australia is lacking in both the Emydas and 

 Trionychidae, the latter being also absent from South America, 

 while the three southern continents are almost the sole possessors 



