Occasional Papers of the Museum of Zoology 3 



sets of from four to eight and the number of sets found in a 

 single plant varied from one to four. They were often at- 

 tacked by a fungus which destroyed them, but when this had 

 occurred sufficient gelatinous matter remained to show that 

 the eggs which survived were not the complete set. 



In 1913 the eggs were first observed between July 19 and 

 23, but it was evident that at this time most of them had 

 hatched, and a number of recently hatched young were found 

 in the plants. In the vSan Miguel collection there are eggs 

 collected on April 24, 1914, which have small embryos. 



The eggs are large and transparent and the developing 

 embryo floats freely in a fluid. The smallest eggs (five milli- 

 meters in diameter), those from San IMiguel, contain the 

 youngest embryos. The latter are about four and three-fourths 

 millimeters in length (exclusive of tail) and have the head, tail 

 and limb buds, but not the body, folded oft". Eggs with slightly 

 older embryos, from San Lorenzo, have a diameter of six to 

 six and a half millimeters, and those which have nearly or 

 quite reached the time of hatching are eight or nine millimeters 

 in diameter and the young are six to eight millimeters in length 

 exclusive of the tail. 



Aletamorphosis is completed in the egg except that the tail 

 is apparently not usually entirely absorbed before hatching. 

 The limbs begin to appear very early, in fact before the body 

 has been folded ofif. The yolk is large in amount and still 

 distends the body of the frog at the time of hatching. The tail 

 is very large, thin and vascular and in the early stages is closely 

 applied to the yolk (Fig. 2). Previous to the time that the 

 young frog leaves the egg the tail decreases in size (Fig. 3). 

 but in the cases observed it still persisted until after the frogs 

 had hatched, either in its embryonic form or as a filamentous 

 appendage or as a small rudiment. It must entirely disappear 



