244 VERTEBRATE ANIMALS OF THE UNITED STATES 



Key to the Species of Malaclemys 



ai On the Atlantic slope M. centrata. 



3.1 On the Gulf slope M. pileata. 



M. centrata (Latreille). Diamond-back terrapin (Fig. 134). Shell 

 rough, each plate having concentric lines of growth; carapace dark 

 olive or grayish in color and 180 mm. long and 130 mm. wide; weight 

 2 lbs.; legs and head spotted; plastron yellow; young individuals whit- 

 ish, with black concentric lines; head without stripes: salt marshes 

 from Massachusetts to Florida, where it feeds on crustaceans and 

 mollusks; highly prized for food. 



Subspecies of M. centrata 



M. c. centrata (Lat.) . Cape Hatteras to Florida. 



M. c. concentrica (Shaw). Size smaller; concentric lines on each 

 plate very distinct : Massachusetts to Cape Hatteras. 



M. pileata (Wied). Similar to M. centrata; carapace with a more 

 or less tuberculate keel and black or brown in color, wdth distinct 

 concentric lines on each plate : Gulf coast. 



Subspecies of M. pileata 



M. p. pileata (Wied). Color black or very dark brown; top of head 

 dark : Gulf coast, from Florida to the Mississippi River. 



M. p. littoralis (W. P. Hay). Color light brown ; top of head white: 

 coast of Texas. 



M. p. macrospilota (W. P. Hay). Each plate of carapace with a 

 large central yellow or orange blotch: west coast of Florida. 



5. Graptemys Agassiz. Map turtles. Carapace depressed and 

 with a keel; plastron without a hinge and immovably joined with the 

 carapace; head covered with a soft skin; lower jaw with a dilatation at 

 the tip: 2 species. 



Key to the Species of Graptemys 



ai A triangular yellowish spot back of eye; keel not serrate. . .G. geographica. 



a2 A transverse cresent back of eye; keel serrate G. pseudogeographica. 



G. geographica (LeSueur) (Fig. 135). Body dark brown and marked 

 with a network of greenish and yellowish lines; plastron yellow; length 

 of carapace 240 mm.; width 180 mm.; carapace circular, notched at 

 the sutures of the marginal plates: central States; eastward into New 

 York and Pennsylvania; westward into Missouri and Arkansas; north- 

 ward to Michigan and Lake Champlain; common. 



