preserved in Chalcedony, 527 



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 in- 

 ternal 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 ex- 

 ample 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 repre- 

 sent, 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 in- 

 vestigations of others, and to prevent them from attributing too 

 much to any bias which might be supposed to have warped my 

 own observations. 



