CLASSIFICATION OF SHELLS. 79
classes in the multivalve division of shells; and this you see must belong to one of them, foi it has many pieces. Now, Lewis, I will read to you what my text-book says about them; and you shall see which description answers best to the shell we have been looking at. First, the chiton, canoe or boat-shell, consisting of several segments, placed transversely, and lying upon each other at their anterior edge."
Lewis put on a considering face, and again examined the shell.
" Let me see," said he, "segment— that means part of a circle, placed transversely—cross-ways, and lying one over the other. I see nothing of the kind : besides, this is not at all