334 Mr. CoNYBEARE on the Origin of a remarkable 



figure (which have seemingly constituted processes attached to such 

 shells) are not unfrequently found in the chalk strata, and that the 

 last in question may possibly have been moulded in a fragment of 

 this. The specimen itself is from the collection of Mr. Parkinson, 

 to whose kind assistance during the course of these enquiries, I am 

 happy to acknowledge myself much indebted. 



I cannot conclude without apologizing to the Society for having 

 occupied so much of its attention, by minute details which I fear 

 may have appeared extremely jejune and uninteresting, as they are 

 confined to the illustration of an insulated fact in the history of 

 organic remains, in itself of very inferior importance, and cannot be 

 said to throw any additional light on the general views even of that 

 branch of geological science with which they are connected. 



Since writing the above I have received from my friend Mr, 

 Buckland the following observations relative to this subject, accom- 

 panied by a recent specimen which appears to illustrate them in a 

 very satisfactory manner. 



** The hollows that afforded a mould for the formation of these 

 singular bodies, appear to me to have been the work of some minute 

 parasitical insect. The small aperture, the cast of which now forms 

 the projecting axis of each globule, was probably perforated by this 

 intruder as the entrance to his future habitation ; having completed 

 this passage, and excavated at its termination a cell suited to his shape 

 and convenience, he appears by the aid of a delicate auger or pro- 

 boscis to have drilled many minute and almost capillary perforations 

 into the substance of the shell on every side around him, taking 

 care to leave always partitions sufficient to support the thin ex- 

 ternal plate of shell which formed the roof of his apartment. 

 Having exhausted all the nourishment which could in this manner 

 be procured with safety from the vicinity of this first establishment, 



