AN ELECTRON MICROSCOPE STUDY*

Abstract

SYNOPSIS In the fresh water and marine sponges, the Golgi apparatus in the collar cells in each type is differently arranged. In the former there are contractile vacuoles which have no direct connection with the Golgi apparatus; in the latter there are apparently non‐contractile bound vacuoles surrounded by a lamel‐lated osmiophile material; the vacuoles presumably form a water reserve. In the amœbocytes of both types of sponges, the Golgi apparatus is in the form of dictyosomes flattened against the nuclear membrane, and in fresh water sponges these dictyosomes have no direct connection with contractile vacuoles.