146 



The medullary protoplasm contains often chlorophyll, and also 

 diatomin and starch or other amyloid suljstance. . . . The 

 constitution of the cell-wall or cuticle from cellulose, as well as 

 the presence of ciilorophyll and diatomin, and the holophytic 

 nutrition of many forms recently demonstrated by Bergh, has led 

 to the suggestion that the dinotlagellata are to be regarded as 

 plants, and allied to the Diatomacea> and Desmidiaceie. Physio- 

 logical grounds of this kind have, however, as has been pointed 

 out above, little importance in determining the affinities of 

 Protozoa." 



Another reason why the organism in <juestion siiould not be 

 regarded as injurious is tiiat it does not appear to die and undergo 

 decay. Some of those which 1 collected on 2nd April have been 

 in a small bottle for ten days without change of water ; and 

 although the water swarms with bacteria and infusoria, they 

 show no traces of decomposition ; they are, in fact, still alive, 

 but motionless. After remaining in the bottle for ahout four 

 days they settled down to the bottom, and ever since they have 

 been undergoing certain changes , the necleus acquired a bright 

 red colour, and afterwards divided into two nuclei ; after division 

 they began to enlarge, and the rest of the contained protoplasm 

 was gradually absorbed, and finally there were formed two large 

 orange-coloured spores. Tliis condition is evidently the well- 

 known encysted state, which obtains in many of the lower plants 

 and animals. When encystment takes place, spores in most cases 

 ai'e provided with a thick cell-wall, and are endowed with a great 

 power of resisting all kinds of injurious intluences, so much so 

 that many of these resting spores may be boiled, or kept in a dry 

 state for a lengthened period, without destroying their vitality. 

 If, in spite of such unfavourable conditions as mentioned above, 

 they are capable of attaining to the encysted state, there is no 

 reason to suppose that tiiey would do otherwise when in their 

 natural habitat. No doubt many of them may die, through 

 injury, and make the water foul ; but still there is no trace of 

 the dead bodies of the Peridinia on the surface of the nmd, or 

 in the water where they are abundant. 



If the organism does not die in large numbers, and its composi- 

 tion is not likely to be injurious, how has it acted so injuriously 

 on the littox'al fanna 1 This is a difficult question to answer 

 without direct experiment on the organisms affected. There 

 are, however, several ways in which this may have been brought 

 about, without supposing that the efi'ects are the result of any 

 poisonous qualities, or that they arise from the death and decom- 

 position of the Peridinia themselves. The bivalve mollusca have 

 evidently been the most affected, and their decomposition has had 

 some intluence in killing the limpets, periwinkles, and other 

 animal life. The dcjitli of the bivalves may be attributed to 

 several causes ; the Peridinia may have been present in such 



