OTHER DIPNOI 
gills of the fish, which are adequate enough in favourable 
conditions. It is in fact exactly in the condition of a 
rather elderly tadpole. The very young tadpole has 
merely gills like a fish; later on, the lungs appear, 
while the gills persist ; later still, the gills vanish and 
the lungs alone remain: it is, however, now a frog. 
Cevatodus remains for its whole life in the tadpole con- 
dition. It would not be a gross exaggeration to describe 
it as a huge scaly tadpole. 
The Australian mud fish is one of those “ friendless ”’ 
creatures, a survival from past times, when creatures 
were apt to be a little less decided as to their relation- 
ships than at present. It is a link between fishes and 
amphibians. Cevatodus itself has not a tadpole; but 
its near allies, the African mud fish, Protopterus, and 
the South American Lepidosiven, have newly-hatched 
larvee which are immensely like young tadpoles. Every- 
body must have noticed the way in which the tadpoles 
of our common frog hang on to the leaves of aquatic 
plants by their chin, which they press firmly thereto 
as the Red Queen pressed her chin upon the shoulder 
of Alice. A sucker achieves this anchorage, and the 
same sucker is present in the young mud fishes of 
America and Africa. The Paraguayan mud fish, once 
so scarce that it was represented in European museums 
by about three specimens, has long furnished a succu- 
lent meal in certain regions of South America. It has 
been brought home in abundance and carefully studied 
by Professor Graham Kerr; it is therefore not by any 
means unlikely that the visitor to the Zoo will have the 
opportunity of seeing side by side this creature and its 
Australian relative. In any case he will be practically 
certain to have the chance of seeing Protopterus ot 
Africa. 
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