C 149 3 
IX. Some account of the feet of those animals whose progressive 
motion can he carried on in opposition to gravity . By Sir 
Everard Horae, Bart . V. P. R . S. 
Read February 22, 18 16. 
The house-fly, as is well known, is capable of walking 
upon the ceilings of rooms, in which situation its body is not 
supported on the legs ; but the principle, by which it is en- 
abled to do so, has never been satisfactorily explained, owing 
to the animal being too small for the feet to be submitted 
to anatomical investigation. 
I was not aware that any animal of a much larger size was 
endowed by nature with a power at all similar, so as to admit of 
this very curious principle being investigated, till Sir Joseph 
Banks, a few months ago, mentioned that theLacerta Gecko, 
a native of the island of Java, comes out of an evening, from 
the roofs of the houses, and walks down the smooth hard 
polished chinam walls, in search of the flies that settle upon 
them, which are its natural food, and then runs up again to 
the roof of the house. Sir Joseph Banks, while at Batavia, 
amused himself in catching the Lacerta Gecko, by standing 
close to the wall, at some distance from the animal, with a 
long flattened pole, which being made suddenly to scrape the 
surface of the wall, knocked the animal down. 
He has procured for me a specimen of a very large size* 
