Observations on the development of the excretory system in Turtles. 705 



offering some apparently anomalous cases of division especially in the 

 periderm ; one case of division of a primitive ovum was observed. 



More interesting, however, was it to find a structure apparently 

 exactly like that recently studied by A. Prenant, and which he com- 

 pares to the hypocord of Ichthyopsida. 



In view of the studies of coloration recently made by Th. Eimer 

 and others, I will give briefly the development of the color in Flaty- 

 peltis. The first indication of external color is the appearance of a 

 single row of dots at regular intervals along each side of the spinal 

 column. These become quite dark round spots before others come. 

 Then similar markings appear at irregular intervals between these 

 and the edge of the carapace. But the definite number seems to be 

 established while the remainder of the embryo is perfectly white. At 

 a somewhat later stage the whole of the embryo aside from these 

 dots acquires suddenly a uniform pale gray tint which gradually be- 

 comes more opaque, but not dark. The dorsal side is darker than 

 the ventral which at some time after hatching turns white. The ori- 

 ginal spots remain, but except on the head and around the edges 

 each appears to spread so that before hatching it becomes a small 

 circle of dots which may have one or a cluster in the middle. These 

 seem to develop proportionately with the growth of the turtle and a 

 turtle a foot long showed no change in the character of the color 

 except that the under side of the carapace had become white, I have 

 seen much older turtles, eighteen inches and more long, in which the 

 general body color seemed to have deepened so as to conceal the 

 markings for they appeared a very dark uniform brown or black, but 

 I have not followed the changes here. 



Some may care to know the order in which motion is developed. 

 The first motion which 1 detected was the flexing of the head ven- 

 trally from the point where the neck joins the carapace. Later the 

 mouth may gap and close but aimlessly. After the embryo has ac- 

 quired color and seems quite a turtle, it draws back the head towards 

 the carapace and opens and closes the mouth with definiteaess. The 

 fore feet complete their development first and immediately take the 

 swimming motion if the animal is put in any liquid. The hind feet 

 follow as soon as developed. From these facts it is clear that a 

 turtle does not need to be taught how to draw in the head to bite 

 or swim. 



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