104 Mr Budgett, The Habits and Development, etc. 
to the rootlets thus laid bare. The hatched larvae are provided 
with six cement organs on the surface of the head. From them 
a delicate rope of mucus is spun often nearly the length of the 
body of the larva ; by this fine rope the larvae hang suspended 
from the rootlets until the yolk-sac is absorbed. 
It is remarkable that the larvae of Gymnarchus and Heterotis 
are both provided with long protruding gill filaments which have 
hitherto, I believe, been only once recorded in the Teleostomi; 
and that Sarcodaces and Hyperopisus are provided with con- 
spicuous cement organs on the head ; these cement organs on the 
head of the larva have usually been regarded as characteristic of the 
Ganoidi. 
It is thus seen that the conditions by which fishes, which breed 
in tropical fresh waters, are surrounded is conducive to the develop- 
ment of very various accessory organs in the larva, both for the 
purpose of respiration and also of preserving them from harmful 
contact with their surroundings. 
