species have large yellow or red markings on the sides of the head and neck, 

 above and behind the eyes. The shape of these patches should be noted care 

 fully. As with most animals, reds bleach out badly in preserved specimens. 



Considerable variation in pattern or form complicates identification at 

 times. All turtles, when young, have relatively long tails and keeled cara' 

 paces. Young soft-shells frequently show no signs of tubercles on the front 

 margin of the carapace, although the presence or absence of tubercles in the 

 adult enables one to distinguish species. Recently it has been shown that one 

 supposed species, Pseudemys troostii, is very likely only a color phase of the 

 adult male of Pseudemys elegans. If this is generally accepted, the name troostii 

 will be used for both forms, since it has priority over elegans. Critical studies 

 of other members of the Pseudemys group may show other synonomy in clas' 

 sification. 



Problems For Study 



Where turtles can be observed under natural conditions or close ap' 

 proximation of them, much information may be secured. We know little 

 about food habits, beyond the fact that few, if any, are strictly carnivorous or 

 strictly herbivorous. A few kinds are condemned because they are reported 

 to compete with fishermen, but careful studies might show that they are of 

 value in eliminating the unhealthy fishes slowed down by disease or parasites, 

 or that their food may consist largely of non-game fishes, which are rivals of 

 the game fish. It is probable that turtles, like birds, change their menu with 

 the change in seasons. 



Winter habits are also little known. Market hunters probe in swampy 

 areas for snapping turtles during fall and spring. Wood turtles apparently 

 winter in small streams, while box turtles burrow in soft soil. More detail on 

 place and time of the winter rest should be recorded for all species. 



Mating habits are also imperfectly known, as are incubation periods and 

 rate of growth under normal conditions. Turtles may be marked for future 

 recapture and study by cutting notches in the edge of the shell. 



Variation from the normal in plates or scutes is interesting and of un- 

 known significance. A not rare anomaly is the development of a double row 

 of vertebral plates. 



Variation in color also deserves study. Observations on young turtles 

 suggest that diet and health may affect the red head-markings on some species. 

 The gradual obliteration of the yellow markings of the shell and body of some 

 of the males of the form known as the Cumberland terrapin, as it transforms 

 into what was once thought to be another species, is an outstanding example of 

 color change. This case may depend on sex hormones, a possibility open to 

 experimental test. 



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