xiv INTRODUCTION. 
TERRESTRIAL MoLiuscaA.— Geographical Distribution (continued). 
GUATEMALA Hownpuras 
Mexico. (with Tabasco, Chiapas, AND NICARAGUA. Costa Rica. 
and Yucatan). SALVADOR, 
Panama, 
Chiapas. and EH. and EB. 
N.W.) Centr. |S.W.} E. | Taba 0, Yucatan. | N. | Centr.|S.W.] W. | E. | W. | Centr.) N.E.] W. |Centr.| E. 
Holospira ........ 2 5) 2) 4 
Epirobia .......... ae fou. | we | 2 2 1. 4 1 
Cylindrella ........ .. 
Macroceramus ....| .. 1 .. 
Opeas .......-.06- Le 3 2 
Subulina.......... Le .s 
Pseudosubulina .. 
Spiraxis ........6. - a _ 
Tornaxis .......... .e .. a es .- .. 1 
Leptinaria ........ .. a .. | 2 1 a .. _ 
Tornatellina ...... .. .. oe | ee Le a .. _ an re 1 
Melaniella ........ .. a we |e 
Cecilianella ...... .. . . | 1 
Oryzosoma ........ - 
Pupa ...sseeeeees 2 
Pupoides.......... 1 
Succinea.......... 1 
Xanthonyx, | 
Cryptostracon.. | 
Ariolimax ........ 
Philomycus ...... 
Limacide ........ . .e .. 
| Veronicella........ . .e 1 
| Carychium ...... Le 
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The chief zoo-geographical interest in the land and freshwater Mollusca of the 
region under investigation lies in the intermingling of the North and South-American 
forms within its limits (rather than in the endemic species), and the relationship of 
the fauna to that of the West-Indian Islands, and also of that of the two slopes, 
the Atlantic and the Pacific, the one to the other. 
The most characteristic genera of land-shells inhabiting Mexico and Central 
America, or those including the greatest number of species, are Helicina, Glandina, 
Streptostyla, Polygyra, Ortalichus, Otostomus, Eucalodium (with the nearly allied 
Celocentrum), and Holospira (including Epirodia). Each of these has a somewhat 
different distribution. 
HELIcINA is very rich in species in the West Indies, moderately so in South America, 
