figure (which have seemingly constituted processes attached to such shells) are not infrequently 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, accompanied 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 proboscis 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 external 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,