97 
the Peruvian Squirrel (S. variabilis ), the Red-bellied 
Squirrel {S. aureogaster ), and the Brazilian Squirrel ( S . 
cestuans). 
Several specimens of the pretty little European Red Squir¬ 
rel (S. vulgaris) are also kept here. 
Near by is a cage containing some Striped Gophers ( Sper - 
mophilus tridecimlineatus). The spermophiles form a large 
sub-group of the squirrel family; they live in burrows in the 
ground, but are directly connected with the tree squirrels 
by almost insensible gradations of form, one of which is the 
Line-tailed or Mexican Rock Squirrel (S. grammurus). 
It is difficult to distinguish this species, without close exami¬ 
nation, from the true squirrels, which live in trees. The 
striped gopher is found from western Michigan to the Missouri 
river and south to Arkansas. 
Richardson’s Spermophile (S. richardsoni ), the Gray 
Gopher ( S.franklini ), and the Pouched Gopher ( Geomys 
bursarius) are also North American forms. 
The Chipmunks or Ground Squirrels, of the genus 
Tamias , are another link in the chain of progression from 
gophers to squirrels; many species are found in North Amer¬ 
ica and Asia. 
