636 * The Development of the Tree-toad. [August, 



THE DEVELOPMENT OF THE TREE-TOAD. 1 



A RECORD of several seasons gives the appearance of Hyla 

 versicolor in the spring, in Milton, Massachusetts, from 

 about the 1st to the 10th of May. Tadpoles of this species I 

 have found most abundant in the water of small, still, shadowy 

 ponds near large trees. The eggs are attached singly and in 

 small groups for a distance of one or two yards along the grasses 

 which grow up and rest on the water. Unless the grass is parted 

 they are not readily seen. The gelatinous substance surrounding 

 the eggs is exceedingly thin. When first laid they are of a drab 

 color on the upper surface, which becomes lighter after a few 

 hours in the water. The under surface is white; the extent of 

 this color varies ; in some cases only a spot of drab is seen on an 

 otherwise white egg. The period of egg-laying, according to my 

 observations, extends from the first week in May to July. The 

 development of the egg is rapid, being accomplished within forty- 

 eight hours. When first hatched the tadpole is about a quarter 

 of an inch long, of a pale yellow color, dotted with olive on the 

 head and sides of the body. During the first week the external 

 gills are developed and resorbed. At the same time the olive 

 color gradually increases and deepens till it extends over the up- 

 per surface of the tadpole. A fine dotting of gold color also 

 appears on both upper and under surfaces. In the water, how- 

 ever, they look black. The holders, at first so prominent, disap- 

 pear within ten days. The head and body are short. The tail is 

 broad and thick. The eyes are prominent, set widely apart, and 

 of a brilliant flame color; the iris in some specimens is quartered 

 by dark lines. The lips are broad. The nostril openings and 

 two perpendicular lines on the muzzle, also a line from before the 

 eyes down each side to the tail, are gold colored. Transverse bars 

 of the same tint on the upper edge of the tail are sometimes 



The tadpoles are shy and quick in movement as young fishes, 

 moving through the water with the least perceptible motion o 

 the tail. They do not collect together, but where there is room 

 enough, each tadpole goes its own way independently. They are 

 hardy, and probably owing in some degree to their quick move- 



1 Abstract of a paper published in the Proceedings of the Boston Society of i a u 



