They are spherical, oval, fusiform, or rod-like, and are always found in the cytoplasm, never in the cell-sap. They appear to be permanent organs of the cell, and are transmitted from one cell to another by division.
Shell fusiform, with elongated spire; margin of shell and mantle notched.
Foot narrow; dorsal papillae linear or fusiform, in several - series.
If the roots are examined numerous fusiform swellings are found upon the smaller rootlets.
(Cacoecia gallicolens), of the family Drepanulidae, causes the stem of a creeping plant, on the pith of which it apparently subsists, to swell up into a fusiform gall.'