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Observations on the Ckelonians 



of North America. I. 

 DR. R. W. SHUFELDT, C. M. Z. S. 





As in most other countries of the 

 world, all the various forms of terrapins, 

 turtles and tortoises are well represented 

 here in the United States, and when taken 

 as a group of the Vertebrata, these repre- 

 sent the Chelonia of North America. 

 Our tortoises are wholly terrestrial forms 

 and so will not concern us in the present 

 connection (Terepene, the "Wood Ter- 

 rapin," and Testudo) ; possibly the large 

 marine species (Sphargis, Thalassoche- 

 lys, and Chelonia) may be referred to 

 further on, while it is my intention, in 

 this series of articles, to devote the space 

 to brief, illustrated descriptions of our 

 turtles and terrapins, as these, at various 

 ages, are kept in aquaria everywhere. 



Strictly speaking, the true turtles are 

 the big marine species ; though in various 

 parts of the country nearly all of the 

 smaller fresh water species are called tur- 

 tles — the edible ones sold in the markets 

 are usually known as terrapins. Fre- 

 quently we find these two vernaculars 

 applied indiscriminately. The name ter- 

 rapin is very generally given to the 

 famous "Diamond-back" {Malacoclem- 

 111 ys palustris) ; next to it the pond tur- 

 tles of the genus Chrysemys, while the 

 snappers and soft-shell species are almost 

 without exception referred to as turtles. 



Our largest genus of pond or river 

 turtles is the genus Chrysemys, and it 

 contains quite a long list of species that 

 occur in suitable localities all over North 

 America, the West Indies, -and parts of 

 South America. This great host of forms 

 has been but partly worked up. As they 

 doubtless hybridize in many districts 



where the limitations of range of various 

 species and sub-species are defined, and, 

 further, as shape, size and coloration var- 

 ies immensely within the species and sub- 

 species for every known one of these in 

 the list, the problem of exact identifica- 

 tion is still further complicated by such 

 sexual variations as may be present in 

 the case of any species of the genus. 



Our eastern form has a distribution 

 over all eastern Northern America, 

 where, among those who have studied 

 these animals, it is known as the Eastern 

 Painted Turtle or Terrapin (C. picta). 

 I have examined and compared a great 

 many hundreds of them, and expect to 

 study others in the future. Typical indi- 

 viduals of this species are not difficult to 

 identify. As we know, the shell of a tur- 

 tle is divided into an arched upper part or 

 carapace, and a lower, ventral, or fiat 

 part, called the plastron. These are gen- 

 erally overlaid with shields of various 

 sizes and contours, and in the main they 

 have a pretty definite pattern for any par- 

 ticular species. The outer, terminal row 

 on the border of the carapace are called 

 the marginal scutes, or shields. 



C. picta rarely exceeds eight inches in 

 length, and its markings usually fade in 

 old age. A typical specimen of five 

 inches in length has the entire plastron of 

 a rich immaculate yellow ; there are rather 

 broad, brilliantly red emarginations to the 

 marginal scutes above and below. The 

 stripings on the head and limbs are of a 

 fine Naples yellow, with the tail lined 

 longitudinally in a similar manner. 

 Above, the carapace is smooth and com- 



