OP ARTS AND SCIRNCES. 51 



more or less of the same character. One extremely exaggerated case 

 was noticed, in which the cells around the circumference of the frond 

 were enormously elongated. This frond happened to be tetrasporic, 

 and the tetraspores were also greatly elongated and deformed. The 

 contents of the cells present little of interest. The outer cells are 

 filled with a very highly granular {)rotoplasm, in which the nucleus is 

 very conspicuous. The inner ones contain less of the granular proto- 

 plasm, and the nucleus is rather more indistinct. All the cells of the 

 plant are usually colorless, though sometimes they may be tinged with 

 purple, especially the filamentous ones in closest contact with the Poly- 

 siphonia. Of ordinary starch there is no trace to be found, iodine giv- 

 ing only a deep brown color to the whole of the contents of the cells. 

 Tlie walls of the cells are cellulose, and are not remarkable. One in- 

 teresting feature regarding the cells of C. Polysiphonioe is their great 

 variability in the amount of contained food material. This varies 

 from the condition found in the globose cells of the young plant, which 

 are gorged with protoplasm, to the decidedly contracted and starved 

 appearance presented by the cells of some of the adult plants. This 

 latter condition is particularly to be noticed in the tetrasporic fronds 

 which are almost ripe, the growth of the tetraspores having appar- 

 ently taken all the food material held in reserve by the plant. Figure 8 

 shows a tetrasporic frond where the cells are somewhat affected, and 

 is a good example of the condition of the average frond. In Figure 14 

 the cells are seen to be well gorged. The difference in appearance is 

 often so striking as to lead one to think at first sight that plants are 

 not of the same species. 



The development of the frond I was able to follow with considerable 

 certainty, except in the youngest stages, of which fewer specimens were 

 found. As has been said before, the fronds of C Polysiphonice are 

 almost always found in the dichotomies of the host plant, and the 

 reason for this can be explained by the following circumstances. In 

 the axils of the branches of Pulysiphonia fastigiata there is often col- 

 lected more or less organic or inorganic material, and they are also 

 frequently occupied by some of the many epiphytic algse that grow 

 upon this plant. Besides the natural shelter afforded by the axils, 

 these growths enable the spores to become attached before they are 

 able to make their way through the tissues of their natural host. The 

 spore becomes buried in the organic matter collected in the axil, and 

 in this position begins to germinate. The earliest stage of a develop- 

 ing spore of Choreocolax that was found was one where five cells were 

 to be distinguished. The spore had apparently divided into four 



