448 TRANSACTIONS OF THE 



formed into hard stone on the spot where they grew and once flourished. 

 In the Lybian deserts numerous groves of trees have been petrified, cross- 

 ing each other in every imaginable form as they were swept down by the 

 tornado. And in the guano even, which we import from Ichaboe, have 

 been found the beautiful shell of the coscinodiscus, which has resisted de- 

 composition, after having passed through fish, then birds, and finally the 

 action of the elements for many centuries, to gladden the eye of the natu- 

 ralist in its unchanged, original, delicate form, sharp and clear as it left 

 the Creator's hands. These secrets of nature would have been covered 

 with impenetrable darkness forever had it not been for the microscope. 



I found upon examining Ichaboe guano, that it contained brown earthy 

 particles, mixed with sundry crystalline matters of different sizes. Some of 

 them were evidently sand ; others crystals of saline matters. The Peru- 

 vian may be known from the Ichaboe from the fact that it contains very 

 little crystalline matter in comparison. The value of either, however, does 

 not depend upon the crystallization, but upon this organized particles of 

 animalculi of numerous kinds, dried flesh of fish or birds, small shells, 

 sponges, and half digested excrementitious matter. I discovered in Icha- 

 boe guano a most remarkable egg, presenting the appearance of an Indian 

 bow, with a cover attached, through which the insect had made its escape. 

 The substance was hard, like that of isinglass, and profusely ornamented. 

 though it could scarcely be discerned with the naked eye. Birds' eggs 

 generally resemble each other in form, but not those of insects, which are 

 of inconceivable variety and shape, and almost invariably beautifully 

 wrought, representing carved work of the richest description. Butterflies' 

 eggs, that have come under my observation, were of all shapes and sizes, 

 round, cylindrical, elliptical, hemispherical, square, conical, apple-shaped, 

 pear-shaped, and plum-shaped, with surfaces most splendidly ornamented, 

 multiplies by shoots and buds, and possesses the power of reproducing any 

 organs of which it may be accidentally deprived, and the narts so lost soon 

 become complete polypes. 



The water flea, is abundant in fresh water brooks, and ponds — its body 

 is ftovered with plates of shell, overlapping each other ; its eyes are dark 

 crimson. Attached to the lower extremities of the flea, there are sacks 

 containing the eggs, and outside of these a forked tail adorned with a fringe 

 of hair ; the body is often embellished with beautiful tints of a bluish 

 green. 



The boat fly, is abundant in my ponds — they swim on their backs, and 

 use their hind legs as propellers, which are fashioned somewhat like oars ; 

 when disturbed they drop to the bottom ; they obtain perfection at six 

 months old, and deposit their eggs, which are small, and look like jelly ; 

 they shed their skins several times during the summer ; it has three pair of 

 feet fringed with hair ; at maturity it has wings, which are delicate and 

 fragile, but protected from injury by hard cases. 



The glutton is an aquatic animal, that nearly resembles the caterpillar, 

 and is to a certain extent transparent ; under the microscope, in a good 



