Most of the young Chrysemys are very pretty, the ground-colour of the upper shields being green, variegated with yellowish-brown or blackish markings, which often form exquisitely delicate patterns, either concentrical (Ch. concinna, Ch. rubriventris), or more longitudinal (Ch. elegans), or apparently quite irregular. The ground-colour of the plastron is yellow, but the various species are best distinguished, at least in very young individuals, by the arrangement of the dark brown spots and patches. There are, for instance, several pairs of bold lateral and several median patches in Ch. rubriventris; five pairs of ocellated spots in Ch. elegans; only small median patches, where four plastral shields meet, in Ch. concinna; while the plastron of Ch. picta is uniformly yellow.

These water-tortoises are very lively and shy, most so perhaps Ch. picta, which is very quick and active. The food varies, often according to individual fancy. Most of them eat fish. Ch. picta is partial to insects, but it also takes worms. Some of my specimens refused meat for a long time, but ultimately they became so fond of it and of worms, that they came out of the pond to take the food from the fingers; those in the Zoological Gardens of London have developed a taste for biscuits. One of my largest Ch. concinna fasted deliberately for eight months, refusing worms, insects, meat, and frogs, only occasionally sniffing at the food, until it was tempted with whitebait, which it took greedily. It refused, however, smelts and pieces of soles, but after another month it condescended to take meat regularly. Very young individuals live chiefly on flies, which they watch for near the surface of the water; and they are fond of smooth caterpillars, maggots, the larvae of humble-bees, and similar soft creatures. They all spend most of their time in the water, preferably floating near the surface, hidden between weeds; and they are fond of basking. Some of them spend the night in the water, lying motionless on the bottom, with heads and limbs turned in. Others prefer hiding under moss. Those species, which, like Ch. concinna and Ch. picta, are common in the North, are of course perfectly hardy. For the winter they dig themselves holes in the banks near the water, and they do not come out again until the spring is well advanced. The eggs are hard-shelled, mostly long and oval, and they are hatched before the end of the summer. The larger species of Terrapin are eaten.

Ch. picta (Fig. 76), the "Painted Terrapin," of the Eastern United States, e.g. of New York and Long Island, is easily recognised by the much depressed shell, which is absolutely smooth, and without a trace of a keel. The colour above is dark olive-brown or blackish, with broad yellow bands across the anterior ends of the neural and costal shields. Three or four of these transverse bands are very conspicuous. The marginals are red, with more or less concentric black and yellow markings. The pretty red colour, with some black stripes, extends over the bridge, but the plastron itself is uniformly yellow. The soft parts are likewise prettily marked, the ground-colour is black-brown, with delicate bright yellow and red stripes on the sides of the neck, limbs, and tail. The stripes are originally yellow, but they develop an orange or red line in the middle, so that each red stripe is ultimately narrowly edged with yellow; or the yellow and red stripes alternate, for instance on the tail, which is short, narrow, and pointed. The head is further adorned with a pair of conspicuous bright yellow patches behind the eyes, and a smaller pair on the occiput. The black and yellow stripes run across the gape of the mouth, some of the lines even looking as if they had been painted across. The nuchal shield is elongated and very narrow, its anterior edge and that of the neighbouring marginals are finely serrated. Very young individuals are at once recognised by the prominent longitudinal median stripe of bright orange extending over the nuchal and neural shields; the yellow transverse bands are still absent; they appear when the longitudinal line vanishes.

Fig. 76.–Chrysemys picta, "Painted Terrapin." × ½.

The "Painted Terrapin" is one of the few species of which, thanks to L. Agassiz,[[132]] complete data of growth from the new born to old age are known. During the first six or seven years the rate of growth is so uniform that numerous specimens collected at the same time are readily arranged in sets of the same age, simply by the differences they show in their size. The successive lines of growth on the shields indicate the number of years. After the seventh year the age is much more difficult to distinguish in those tortoises, which, like Ch. picta, have a perfectly smooth epidermis. This smoothness is due to the fact that the shields undergo a process of moulting. An upper, quite transparent layer of each shield peels off completely like a piece of mica. I have been able to confirm Agassiz' statement on Ch. concinna in their third and fourth springs, and on a number of adult Ch. picta. The latter were not allowed to hibernate, being kept in a warm tank; they peeled completely during the late autumn, and then the red and yellow colours underlying the newly formed shields appeared very vividly; others moult at midsummer.

Growth of Ch. picta, after Agassiz.

Year.Length of
carapace.		Breadth of
carapace.		Height of
box.		Length of
tail.
millim.millim.millim.millim.
Third042039.5017017.5
Fourth051049021.5020.5
Fifth054051023.5021.5
Sixth059056025023.5
Seventh066060026.5026
Eighth (♂)072.5061028027.5
Ninth (♂)074062028027.5
Tenth (♂)077064030028
Eleventh (♂)080067030028.5
Fourteenth (♂)092074.5033028.5
Twenty-fifth (♀)121092043034
Old ♀129096047037
Very old ♀163113059053

The size of the eggs varies considerably, from 26 by 17 to 30 by 16 millimeters; sometimes they are perfectly round, 17 mm. in diameter.

Ch. concinna.–The specific character by which this Terrapin may be easily recognised is a pair of orange-red broad streaks, which extend from above the eye to the sides of the neck. The general colour is olive-brown above, variegated with yellowish dark-edged lines, which, together with numerous rugosities, radiate from the middle field of each shield. The plastron is yellow, often with blackish symmetrical patches, and sometimes these become confluent and preponderant. Very young specimens are extremely pretty, the ground-colour of the carapace being green, each shield with darker, somewhat concentric markings, most conspicuous and regular on the upper surface of the marginals, where the marks of the adjoining shields form one pattern-system across the dividing lines. The plastron is either uniform yellow or has a few pairs of blackish spots which stand so closely together that they form almost median patches.