During several years I have had frequent opportunities, in my spare time, of collecting and studying the Crinoidea, particularly those of the Carboniferous formation; bat I have not had time, nor do I feel competent, to treat this subject fully in all its bearings. Perhaps, however, a few further notes on what I have observed in connexion with them, and in their relations with the recent as well as with those found in the several geological formations, may have an interest for some of your readers, or may be suggestive of further examination by some one better qualified, by physiological knowledge, for the inquiry.