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GRACE A. DUNN 



granules in a cell is about twice that of the nucleolus. They 

 appear in the tetrasporangium before any nuclear division has 

 occurred, and at the time of theii' appearance the amount of 

 chromatin in the nucleolus does not seem to have been diminished. 

 Bodies which are evidently similar to these granules found in 

 Dumontia have been seen by Lewis in Griffithsia and by Svedelius 

 in Delesseria. They appear in the tetrasporangium in Griffithsia 

 at the time of synapsis and disappear at the end of the first 

 reduction division. These granules are at first small and quite 

 numerous, but later they become larger and the number present 

 in the tetrasporangium increases. Lewis beheves that they 

 have been derived from the nucleus. 



The granules appear in the tetrasporangium in Delesseria 

 at the time of diakinesis. As in Dumontia, they are especially 

 numerous in the cytoplasmic jacket around the nucleus; and, 

 as Svedelius states, might readily be considered as part of the 

 chromatin contents of the nucleus. These granules, as in 

 Griffithsia; are at first small and numerous. Later, there is 

 a marked increase in their size and a decrease in their number. 

 Svedelius is inclined to believe that these bodies did not originate 

 in the nucleus. He thinks their function must be of a nutritive 

 nature, possibly similar to that of the degenerating nuclei in 

 Martensia.'^ In Martensia there is a marked increase in the 

 volume of the chromatophores and all the cytoplasmic contents 

 of the tetrasporangium during the degeneration of 49 of its 

 nuclei. Svedelius believes that the substance of these degener- 

 ating nuclei is used in the formation of this extra amount of 

 cytoplasm. 



Evidence concerning the time of nuclear division in the tetra- 

 syorangium. Only a few stages of nuclear division in the tetra- 

 sporangia have been seen. 



Material was collected at each of the twenty-four hours of 

 the day. Five or six whole plants were fixed in each collection. 

 This material was examined and in every case the nuclei in the 

 tetrasporangia and all the vegetative nuclei observed were in 



' Svedelius, Nils, tjber den Ban und Die Entwicktelung der Florideengattung 

 Martensia. Konel. Svenska Vet. Akad. Handl., Bd. 43, no. 7: 1-101. 1908., 



