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carapace, sutures, examples, specimens and blackish


Peendemys palustris (Gmelin).

A series of 10 very interesting examples from Guanica Lake, Porto Rico. On first examination they appeared to represent two distinct species, and it appears that two very great extremes of color variation occur in Porto Rico. Dr. Stejneger pointed out in 1902 that "there are indications at hand that there may be some constant differences between those inhabiting the different islands, but the material at my disposal is not sufficient to warrant an attempt to separate them." Later Dr. Barbour says: "There are specimens at hand from Jamaica (type locality), Cuba, Haiti, and Porto Rico. They do not, however, vary in such a way as to warrant the designation of varieties confined to each island. Stejneger and I (Bull. M. C. Z., 1910, 52, p. 301) had both expected that such subspecies might be defined. As yet, however, the material available for study is very meager. The species is very shy, and is usually confined to lowland muddy pools." Thus, as little appears to be known concerning this species, a few notes on the variation are given below. All my examples were secured in the lowland lake at Guanica. Dr. Stejneger's figures 185 and 186 represent what may be considered typical (in a restricted sense) of palustris. This shows specimens which have the pale lengthwise lines on the sides and lower surface of the head. In this form the carapace is more of a uniform color, without dark blotches or spots, and the plastron may be marked with dark lines along the sutures of the plates, which may vary to very obsolete or even be wanting. About 7 of my examples, representing both sexes of this form, are in the collection.

The remaining three specimens exhibit a different pattern of coloration. They also differ in having the front claws a little longer than the longest of the preceding. The carapace in all is decidedly paler over and about the anterior third than the rest of its extent, showing but few markings, and these now obscure, though the sutures of all the plates are conspicuously blackish. The sutures of the plastron and all the lower marginal plates of the carapace are also marked with blackish. The carapace is also largely speckled or blotched with darker. The color-pattern of the head is strikingly different from the other specimens and is shown everywhere with narrow blackish wavy or vermiculated lines, often broken or irregular. The feet are similar.

The latter variety was first noticed by Gray as Emys

vermiculata,' and the type locality given as tropical America. I have not seen his subsequent though under Trachemys rugosa he gives' the following description of "Emys vermimilata Gray " : "Shell 7f in. Back brown, closely black-dotted; sternum and under side of margin very closely spotted. Sternal shields dark edged." The locality is given as the West Indies. Sowerby and Lear figure the Emys rugosa,' a fairly good representation of the present variety.

The interesting figure by Cocteaus agrees with the above in the speckled carapace and dark-edged sutures of the plastron. The head is streaked as in the examples here allowed as typical palustris.