51�Թ�

Spirula is distinguished from all other existing Cephalopods by the structure of its coiled shell, which in many respects resembles those of the extinct Ammonites, and is not completely internal.

Spirula, spir′ū-la, n. a genus of sepioid cuttle-fishes.

In places in New Zealand, and elsewhere, large fossil deposits of Spirula peroni occur.

After a gale, on looking amongst the wrack cast up by the highest waves, large numbers of our Spirula will be found.

A further peculiarity of the nautilus shell and of that of the allied extinct Ammonites, Scaphites, Orthoceras, &c., and of the living Spirula, is that the series of deserted air-chambers is traversed by a cord-like pedicle extending from the centro-dorsal area of the visceral hump to the smallest and first-formed chamber of the series.