Great credit is due to those observers who have been enabled to give to science both clear and comprehensive views of the anatomy of creatures which have only been presented to them in a spirit-preserved, opaque, brittle, and contracted state; for it is certain that their penetration in this respect could not be successfully brought into exercise without the aid of much knowledge, both bibliographical and practical. Yet there are many whole animals, and, in particular, parts of animals, which must be seen in the living state, to be at all comprehended by even the most brilliant mind; and this fact has induced me to make drawings and notes of many interesting matters connected with the pelagic mollusca, when the living animals fell casually under my own observation. In the present communication, however, I shall confine myself to the genus Clio.