The Terrapins 



vats to prevent them losing fat, are known commercially and 

 collectively as "Sliders." Large examples sell at f i .50 to $2.00, 

 while considerably smaller Diamond-backs about eight inches 

 long are worth fully |6o.oo a dozen. The species of Cbelopus 

 are worthless for market purposes. 



Definition of ibc Genera 



A. Size moderate to large. 6 to 14 inches. 



Shell broad and flattened, with some species rising 

 to a very blunt apex. No concentric grooves on 

 shields, but numerous parallel furrows, extending 

 lengthwise on many of the species. Claws very long. 



Genus Cbrysemys. 



Shell flattened, but rising in the centre to ratner 

 a sharp apex, surmounted by a strongly-defined keel. 

 Shields smooth, or with concentric grooves. 



Genus Malacodemmys. 



B. Size smaller from 3/08 inches. 



Shell low and bluntly rounded. Smooth or with 

 concentric rings. Genus Chelopus. 



The Genus Cbrysemys. The exact standing of these turtles 

 in the United States, as concerns the number of species, is doubt- 

 ful. These terrapin are quite variable, both in the conformation 

 of the shell and in colouration. The writer has before him a 

 series of shells of the Cumberland Terrapin, (Chrysemys elegans). 

 There is a degree of variation in the outlines of the carapace 

 that might greatly confuse the novice. Some of the shells are 

 quite high and have a tendency to be globular; others rise to a 

 blunt apex and are surmounted by a strong keel; a few are 

 decidedly flattened, with a blunt keel. The colouration of 

 the series is likewise variable. Such conditions exist among 

 most of the species. Thus it will be understood that the genus 

 is a difficult one to describe in a popular manner. As little techni- 

 cal work has been done with genus, since the writings of the late 

 Dr. Baur, there are no books of reference to aid in the comparison 

 of various specimens. The writer has given much thought to 

 these terrapin, and has examined fine series of most of the species, 

 but he has encountered many troublesome problems that would 

 take many- months of investigation and many more specimens 

 to solve. Following his idea to exclude technical phraseology 

 from this work, the writer has found it a hard matter to define 

 one species from another. 



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