132 
FASCICULI MALAY BIASES 
The superciliary ‘ horns * are merely indicated in the half-grown specimen 
and in a young perfect specimen, and no trace of them is to be seen in one, 
only half as long, which has retained the tail fully developed. The tympanum 
is distinct. Until more specimens have been examined, it is, in my opinion, 
safer to designate this frog by the varietal name aceras than to describe it as 
a new species. 
‘ The adult appears to be nocturnal, and all the specimens that I have 
seen under natural conditions have been taken in dead tree-trunks lying on 
the jungle floor. The larvae were obtained from a pool, not more than a 
foot-and-a-haif square, in a little watercourse of partially artificial origin. I 
took a number of specimens in the same pool at the beginning of May, in 
1899. They occupy the extreme edge, where the water is so shallow that 
their tails almost touch the bottom when they are suspended from the surface 
film ; and when the pool dries up, as it does in comparatively dry weather, they 
conceal themselves among the mud and dead leaves that remain, living, at any 
rate for some days, under such conditions. Nevertheless, we were unable to keep 
them alive in captivity for more than a day or two, probably because we did 
not put them in sufficiently shallow water. Their food, judging from the 
contents of their intestines, consists of algae and minute organisms, both 
animal and vegetable. I do not believe that it is possible for them to rasp 
the leaves of water-plants, as Dr. Gadow suggests. As a rule, they hang 
from the surface film, as in Dr. Gadow’s figure, but occasionally they sink to 
the bottom, where they often lie on one side for a few minutes before 
returning to the surface. The moment that they commence to sink, the funnel 
round the mouth collapses, taking on the form of a pair of horns, curling 
backwards along the side of the head ; but, as they touch the surface again, it 
re-expands into a regular parachute form : I was able to obtain photographs 
illustrating this action. It is probable that development is liable to be protracted 
by drought, as we found specimens in the same pool both at the end of April 
and again in September and October, and those taken in the autumn were, 
with a few exceptions, only a very little further advanced than those taken in 
spring, an unusually dry summer having intervened. It is, however, possible 
that they may have belonged to different broods, and I am only led to make 
the suggestion that this was not so, by the fact that on one occasion, even in 
September, when the rains should be commencing, the pool dried up almost 
completely, and the tadpoles took refuge in the mud. The funnel round the 
mouth exhibits some curious histological features, which will, I hope, be 
described in a subsequent paper.’ 
