Note 13 — Chapter I · VOYAGE FROM NEW YORK TO RIO DE JANEIRO.

This lecture was accompanied by careful descriptions and drawings on the blackboard, showing the structural differences between these groups. These are omitted, as they would have little interest for the general reader. The chief object in reporting these lectures is to show the aims which Mr. Agassiz placed before himself and his companions in laying out the work of the expedition, and these are made sufficiently clear without further scientific details.