GEOGRAPHICAL DISTRIBUTION. J 0.3 



cics of the preceding section extend into this, and almost 

 all of those belonging to the next succeeding section are 

 common to it ; but it has its own peculiar species "which 

 prevail particularly in the mountainous parts of its most 

 southerly portion. Among these are Helix sjnnosa, 

 jr. major, H. cumherlandiana, H. suhplana, H. gularis, 

 H. rotula, H. leporina, and H. lasmodon. The physical 

 conditions of this section are peculiarly conducive to 

 the development of testaceous variation ; hence we find 

 here the carinated and heavily-ribbed Helix palliata, the 

 deep-ribbed Helix alternata, and others. In it the 

 genera Limax and Tebennophorus are very abundant. 

 This section, already distinguished by a larger number 

 of pecuHar species than either of the others, has been 

 but partially explored. Being in its greater part a 

 mountainous region, subject to climatal influences differ- 

 ent from those of the coimtry north of it, it may be 

 expected to furnish a still larger number of yet unob- 

 served species, and would doubtless well reward the 

 industry of any naturalist who shovdd thoroughly recon- 

 noitre it. Like the preceding, it extends beyond the 

 Mississippi River, but its limits are there unknown. 



Section 4. The Noi'thern interior Section. This 

 includes the country between the Ohio River and the 

 Great Lakes, and between North Carolina and New 

 York and Vermont. Its character is much like that of 

 the preceding section, except that its winters are longer 

 and more severe. Its boundaries on the north-east and 

 north-west are not well defined, and it extends like the 

 preceding, west of the Mississippi River. The influences 



