The question of the nature of Coccospheres and Rhabdospheres cannot be regarded as definitely settled. It has been shown by J. Murray, and more recently by G. Murray and V. H. Blackman, that on the solution of the calcareous material by a weak acid there remains a small gelatinous body apparently protoplasmic in nature. We may at least express the opinion that Schütt’s suggestion as to their being inorganic must be ruled out of court. It would appear that they are extremely minute unicellular organisms characterised by a delicate calcareous armour consisting of numerous plates or scales. We know nothing as to their life-history, and cannot attempt to determine their affinities with any degree of certainty until further facts are before us. It is not improbable that they are algae of an extremely minute size, and the evidence so far obtained would lead us to regard them as complete individuals rather than the reproductive cells of some larger organism. Mr George Murray is of opinion that they are certainly algae, but he considers that they cannot be included in any existing family. It is conceivable that they may be minute eggs or reproductive cells of animals or plants, but on the whole the balance of probability would seem to be in favour of regarding them as autonomous organisms. III. SCHIZOPHYTA. A. SCHIZOPHYCEAE (CYANOPHYCEAE). B. SCHIZOMYCETES (Bacteria). In this group are included small single-celled plants of an extremely low type of organisation, in which reproduction takes the form of multiplication by simple cell-division, or the formation of spores. The characteristic method of reproduction by division has given rise to the general term Fission-plants for this lowest sub-class in the vegetable kingdom. In many cases the members of this sub-class contain chlorophyll, and associated with it a blue-green colouring matter; such plants are classed together as the Blue-green algae, Cyanophyceae, or Schizophyceae. Others, again, are destitute of chlorophyll, and may be conveniently designated Schizomycetes or Fission-fungi. Seeing how close is the resemblance and relationship between the members of the sub-class, it has been the custom to include them as two parallel series under the general head, Schizophyta, rather than to incorporate them among the Algae and Fungi respectively. A. SCHIZOPHYCEAE (CYANOPHYCEAE or Blue-green Algae). _Chroococcaceae._ Thallus of a single cell, the cells may be either free, or more usually joined together in colonies enveloped by a common gelatinous matrix, formed by the mucilaginous degeneration of the outer portion of the cell-walls. Reproduction by means of simple division or resting cells.