supposed by some of my friends to be examples of the fact under review. They appear to belong to the tribe of Zoophytes.
29. The singularity of this occurrence has induced me to give a figure of it. I know not indeed that any other example than the present one has been produced of an animal substance of this nature preserved in chalcedony. The stone which contains it is a striped onyx agate, and is part of a ring in the possession of the Earl of Powis. Its fortuitous section by the lapidary has exposed the internal as well as the external side of the chrysalis, from which the fly had escaped previously to its lapidification. Its structure points it out to be the pupa of a lepidopterous insect, probably of a moth.
30. I have figured this, although I conceive it to be another example from the Zoophytes, because I suspect that it has been mistaken for the fructification of a moss.
It is proper to remark that the figure attached to each specimen is intended to express the number of times it is magnified in the drawing.
Independently of the figures which I have now given, I possess numerous other varieties, which I thought it superfluous to represent, as they afforded no striking peculiarities. I have chosen the figures among the most perfect, as well as among the most obscure, for the purpose of illustrating the one by the other; and I have also added the mimic resemblances to guide, if possible, the investigations of others, and to prevent them from attributing too much to any bias which might be supposed to have warped my own observations.