Metamorphosis of the e? Non-aquatic Frog” of the 
Palau Islands, Western Carolines 
Kenji Atoda 1 
INTRODUCTION 
The frogs in the Palau Islands seldom, if 
ever, leave their refuges during the daytime, 
but after sunset they are found easily in weedy 
places. There are two types of frogs, the large 
and the small, of which the larger is the 
female and the smaller the male. The male 
has strong jumping powers. Neither type has 
any webs between toes or fingers. 
The adult frogs are well known to the 
Palau natives, who call them "gedegedug,” 
"hedehedh,” or "dechedech,” but it is inter- 
esting to know that no one has seen their 
tadpoles. I made a search for the tadpoles in 
some pools and ponds, but without success, 
and the question soon arose as to where and 
how these frogs pass through their larval 
stages. During my long stay in the Palau 
Tropical Biological Station on Koror Island, 
I was fortunate several times in discovering 
the spawning place of the frogs, and was 
thus given the opportunity to study their 
metamorphosis. 
Here I wish to express my thanks to Pro- 
fessor Shinkishi Hatai, then Director of the 
Palau Tropical Biological Station, for his 
kind guidance throughout the observations. 
METAMORPHOSIS 
The eggs collected from the natural spawn- 
ing place were placed in a petri dish, the bot- 
tom of which was covered with a wet filter 
paper to maintain a humidity of about 100 
per cent. The room temperature ranged from 
25.1° to 31.0° C. throughout the period of 
observation. 
1 The Second Higher School, Sendai, Japan. 
Manuscript received July 20, 1949. 
The observations were made on one hatch, 
of which the youngest larva is shown in Figure 
la. The egg is covered with a rather tough 
gelatinous membrane and just after spawn- 
ing it measures about 6 mm. in diameter. A 
large mass of yellowish- white yolk is attached 
to the abdomen of the larva. The three parts 
of the body — head, trunk, and tail are dis- 
tinguishable. The central part of the head Is 
somewhat hollow, and rudimentary eyes ap- 
pear on both sides. The mouth is a shallow 
invagination not yet open. The end of the 
tail is bent toward the abdomen. Each pair 
of limbs appears as rounded and protuberant 
swellings, the hind limbs being slightly larger 
than the forelimbs. Fine blood vessels ran 
along the forelimbs, then toward the abdo- 
men and finally branch into networks. The 
melanophores are not yet visible. 
On the second day (Fig. 1 b), a pair of 
well-developed eyes appears and the mouth 
opens, the tail becomes much longer, and the 
vascular system is conspicuously developed. 
The melanophores appear scattered over the 
head and trank. 
On the fourth day (Fig. 1 c) , the mouth Is 
wide open and a pair of external nares is 
seen on its upper part. Numerous blood ves- 
sels are distributed over the abdominal re- 
gion; the heart, which is perceptible through 
the skin, beats at an average rate of 120 times 
per minute (at a temperature of 30.8° C). 
On the seventh day (Fig. Id, e ) , the 
yolk decreases and , becomes flattened dorso- 
ventrally. Five toes can be distinguished in 
the hind limbs but the forelimbs are hidden 
by the yolk mass. The melanophores increase 
in number on both the head and trunk. 
On the tenth day (Figs. 1/; 2a) , both the 
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