Note 155 — SYSTEMATICS AND HISTORY

C. E. v. Baer clearly discriminated between the type, the degree of organisation, and the histological structure. All these three topics indeed have to be taken into account separately; the third alone is of the adaptive type. All of them may be independent of each other: the Amoeba may be as adapted histologically as is a high vertebrate, but it is of much lower type; and in its own type it is of a lower degree of organisation than Radiolaria are.