XVili 
Geographical Distribution of the Species in Mexico and Central America. 
INTRODUCTION. 
FRESHWATER MOLULUSCA. 
Mexico 
(with Tabasco, Chiapas, 
GUATEMALA 
Yucatan, and 
British Honduras). 
HonpDvuras 
AND 
SALVADOR. 
NICARAGUA. 
Costa Rica. 
PANAMA, 
Centr. 
Physa, 
a. Aplecta ........ 
b. Stenophysa 
c. Alampetis 
Limnea ............ 
Planorbis. 
. Helisoma........ 
. Menetus 
. Gyraulus 
. Spiralina 
. Taphius ........ 
. Hippeutis 
g. Planorbula 
Ancylus ............ 
Gundlachia 
Ampullaria.......... 
subgen. Ceratodes 
Vivipara 
Valvata 
Cochliopa 
Amnicola 
Tryonia ............ 
Pachychilus. 
a. Glyptomelania 
eet ee 
ee ee eo eee 
eo eee eee 
“Sa Qa Oa 
Cr 
oe eee ee eee ee 
ov ee ee eeee 
ee en 
b. Pachychilus, s. str.. 
c. Oxymelania 
Semisinus 
Neritina. 
a. Alina ......-... 
b. Neritzea 
Unio. 
a. Crenodonta 
Psoronaias ...... 
. Arotonaias ...... 
. Pleurobema...... 
. Sphenonaias 
Nephronaias 
. Simonaias 
. Lampsilis 
Elliptio ........ 
. Uniomerus 
l. Metaptera 
Anodonta. 
| fa. Anodonta, s. str... 
(|e. Patularia........ 
ae ce nreereee 
Tp SQ tia Qeo 
se ee ee 
rt © 
2? 
a ell NS) 
mee! 
1? 
met 
KH oo 
Pee bl DWN 
Or 
o> bo 
bo: 
DH WHEE? 
Yucatan, 
Belize. 
22 
Ww. 
Centr. 
and EH. 
N.E. 
HE oo 
bo bor 
cata 
a 
io 
2 (3?) 
call aeis 
ee 
re OO 
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HHH OO 
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