Journal of the Marine Biological Association of the United Kingdom 63: 135-160 (1983).

The morphology and microanatomy of two different phases in the life history of a single new marine choanoflagellate (Proterospongia choanojunctasp. nov.) have been documented and described with the aid of light microscopy and from electron microscopy of whole mounts and sections of material in clonal culture. Completion of the life-cycle has been repeatedly acheived in cultures established from single cells, regardless of which phase is used as a starting point. One phase is colonial and motile (the Proterospongia phase) and the other unicellular and sedentary (the Choanoeca phase). Taxonomic, nomenclatural and developmental problems are summarized and discussed.