428 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1959 
modify a life history from that of an aquatic organism to that of a 
terrestrial organism. In fact, variability in reproductive pattern 
seems to be characteristic of the lower vertebrates. Diversity of life 
history is certainly well exemplified in the fishes, for example. Thus, 
in the grunions (Atherinidae) the eggs are deposited in sand on the 
beaches. The eggs of the Brazilian Copeina arnoldi are laid in jelly- 
like masses just above the waterline and are splashed by the male 
every 15 or 20 minutes until they hatch after about 3 days. Male 
climbing perch (Anabantidae) make floating bubble nests in which 
the females deposit the eggs. Males of sea catfishes (Ariidae) and 
mojarras (Cichlidae) carry the eggs in their mouths until they hatch, 
and in the well-known pipefishes (Syngnathidae) the female deposits 
her eggs in a brood pouch on the abdomen of the male. Here they 
are fertilized, the eggs hatch, and the young undergo their develop- 
ment. Internal fertilization is practiced by the sharks and top min- 
nows (Poeciliidae), and in these groups the young are usually “born 
alive.” 
In each of these, however, the modification has resulted solely in 
the protection of the eggs from the exigencies of development in open 
water, since the adult itself never becomes terrestrial. This is not 
true of the amphibians. Comparative anatomy teaches us that adults 
of many of the modern forms have developed terrestrial characteristics 
while their reproductive habits still link them to the water. 
It is impossible for us to examine directly the breeding habits of 
those early amphibians that moved their way out on land and gave 
rise to the truly terrestrial vertebrates. However, even today, 275 
million years later, the amphibians are still trying to alter the piscine 
life-history pattern of depositing large numbers of small-yolked eggs 
in open ponds, on the chance that some of the offspring will live 
through to maturity. A study of these attempts may give us some 
clues as to how the change to terrestrialism was made. An examina- 
tion of life histories shows plainly that many amphibians today do 
not at all follow what is known as the “typical” life history. Because 
the study of the amphibians developed largely in the North Temperate 
Zone, and because the frogs of this zone usually spawn in open water, 
with the small-yolked eggs hatching out into tadpoles which swim 
around until they are ready to transform into froglets, we often get 
the feeling that this is the amphibian life history. We are apt to 
overlook the fact that most amphibians live in parts of the world 
where the study of amphibians and reptiles has been least pursued 
and that the “typical condition” as given in an elementary zoology 
text may really, in a sense, be atypical. It may not even have been 
the characteristic pattern of the Carboniferous amphibians. Noble 
(1931) pointed out that the most primitive amphibians living today, 
