604 Badiata. 
merable small apertures or pores, communicating with a 
network of fine canals, which permeate every part of the 
substance and convey to the minute and simple creatures 
which form the living part of this curious compound 
animal, the food and water necessary for their support 
and respiration. These fine canals unite into larger 
passages, leading to orifices of considerable size usually 
placed on prominences of the surface ; from these the 
water streams forth with such force, according to some 
observers, as to be perceptible by the eye. 
The inherent chemical properties of this curious Zoo- 
phyte are very remarkable. When a Sponge has been 
immersed for fourteen or sixteen days in nitric acid 
(diluted with three parts of distilled water) it becomes 
nearly transparent, and when touched with ammonia, 
assumes a deep orange colour, inclining to a brownish 
red. But if much softened by the acid, the whole fabric 
immediately disappears, on being immersed in ammonia, 
and forms a deep orange-coloured solution. A Sponge, 
when boiled, gives out a considerable portion of animal 
jelly. The infusion of a small quantity of oak bark 
causes this to fall to the bottom of the vessel, as a sedi- 
ment, and so entirely changes the nature of the Sponge, 
that, when dry, it crumbles between the fingers ; and, 
when moist, it may be torn like wetted paper. In this 
state we should naturally conclude that it is entirely 
useless : but no ; the operations of chemistry resemble 
a magic wand. Boil the same in water, with caustic 
potash, its latent qualities will be called forth; and, 
behold, a deposition of animal soap ! 
THE FRESH-WATER POLYPI AND THEIR 
MARINE ALLIES. (Bydroida.) 
These are two species, which will fully illustrate the 
nature of the whole tribe. They are found in clear 
waters, and may generally be seen in small ditches and 
trenches of fields, especially in the months of April and 
May. They affix themselves to the under-parts of leaves, 
and to the stalks of such vegetables as happen to grow in 
