SEXUAL DIFFERENCES IN COLORATION IN THE SPOTTED 

 TURTLE, CLEMMYS GUTTATA. 



By S. F. Blake, 



Assistant Botanist, Bureau of Plant Industry, United States Department of Agriculture. 



Very few instances of sexual differences in coloration among the 

 Chelonia are on record. In Boulenger's Catalogue of the specimens 

 of this order in the British Museum mention is made of only two 

 species which present sexual differences in coloration. 1 One of these 

 is Kachuga trivittata (Dumeril and Bibron), an Indian species not 

 represented in the United States National Museum. Boulenger 

 remarks 2 in his description of this species: "The male B. [lege K.] 

 trivittata is characterized by three black longitudinal bands on the 

 carapace, which are absent in the female according to Theobald, 

 whose opinion I am disposed to indorse rather than that of Anderson, 

 who makes a distinct species (B. iravadica) for the specimens (female 

 and yg. male) without bands." The synonym Batagur iravadica An- 

 derson, however, is cited by Boulenger with a mark of interrogation, 

 and the existence of a sexual difference in coloration in this species 

 (Kachuga trivittata) can not be regarded as definitely established. 

 Gray 3 remarks: "This colour [i. e., the three black streaks] appears 

 to be laid on the shell, and flakes off." 



The other species in which a sexual difference in coloration is 

 described by Boulenger is Emys orbicularis (Linnaeus), the com- 

 monest of European turtles, the soft parts of which are described 4 

 as follows: "Head dark brown or black, with lighter dots, which 

 are yellow in the female and pale brown in the male. ..." I 

 have not been able to confirm this statement in an examination of 

 the few alcoholic specimens of this species in the United States 

 National Museum, as those of each sex appear to be spotted alike 

 with pale yellow. 



» Under Cirwstemum integrum (p. 42), Boulenger describes the color of the shield as follows: "Carapace 

 brown, with small blackish dots in the male. . . ." Only three adult specimens are listed— an insuffi- 

 cient series for establishing a sexual difference in color; and Dr. L. Stejneger Informs me that the supposed 

 difference is non-existent. 



» Cat. Chelon. Brit. Mus., pp. 55-56, 1889. 



• Suppl. Cat. Shield Rep., vol. 1, p. 56, 1870. 



* Cat. Chelon. Brit. Mus., p. 113, 1889. 



Proceedings U. S. National Museum, Vol. 59— No. 2382. 



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