Four new species of choanoflagellates from Arctic Canada

By means of electron microscopy applied to wild material prepared as dry whole mounts, descriptions are given of external morphology, including lorica construction, of four new species of collared flagellates, namely: Pleurasiga caudata, Salpingoeca longicaudata, Parvicorbicula serrulata and Diaphanoeca aperta. Reasons are given for the choice of generic names although future changes in some generic boundaries are expected. Aspects of the ecology and geographical distributions are discussed in a preliminary way.