144 Journal of the Asiatic Society of Bengal. [N.S., XIX, 
the disc and the presence of these spines account for the 
adhesive action of the finger pads of the tree-frogs 
adow writes, ‘‘ Various suggestions have been made to 
explain the function of these discs. Suction, adhesion, and 
glueing- on have been resorted to. Suction, throug produc- 
tion of vacuum, is quite imaginary and does not exist.” 
According to this author the yen. of the discs depends 
pon adhesion, which, he says, is greatly enhanced by a 
sticky secretion from the glands of hs animal. He further 
observes that “‘tree-frogs, when hopping on to a vertical 
plane of clean glass, slide down a little probably until the 
secretion stiffens, or dries into greater consistency. Aiter 
a few days I find ‘the glass-walls of their recently cleaned cage 
quite dirty, covered everywhere with their finger marks.” I 

site Sa 
Transverse section gre a finger disc of Hyla annectens 
erdon): 487. 
ave not made any observations on living = ip which 
would enable me to criticise the above statem ut on a 
careful study of ai Spoe material a few points tas occurred 
to me which are worth recordi 
In the first place Ee can Sag no trace of glands in the 
finger-pads of Hyla. The accompanying figure clears this 
point. The fact that a tree-frog slides apes a a when 
hopping on to a vertical plane of glass may be due to the time 
required for adjusting minute epidermal icasonnes on the 
pads into corresponding irregularities on the opp posing surface. 
I make this suggestion on the analogy of the Gecko, in a 
there are certainly no glands to secrete a sticky substan 
The second point observed by Gadow, that the mucnil 
cleaned glass-walls of the cage are rende red dir rty in a fe 
day’s time, may prove no more than that these frogs soil their 
