Note 2 — INTRODUCTION.

Mr. Parkinson states, that in a trilobite which he possessed he thought he perceived the points of the feet; but on endeavouring to detach the piece of rock in which it was embedded, the specimen was entirely shivered, though he worked at it with the utmost care. A portion of the underside of a trilobite (Isotelus gigas) near the anterior edge of the head, was distinctly ascertained, by Dr. Dekay, but only enough to convince him of its analogy in this part with that of the limulus polyphemus no organs of locomotion could be seen. Mr. Stokes, the distinguished fossilist of London, has confirmed the observation of Dr. Dekay, by some dissections of his own.