442 BOTAXICAL GAZETTE \june 



also the 2 terminal cells are at first in close contact, but later 

 become separated (fig. 26). 



The cells of the carpogonial branch in the 4-celled stage may 

 lie in a straight line, or the axis of the 3 terminal cells may form 

 more or less of a right angle with that of the basal cell (figs. 27, 28). 

 The nuclei here furnish evidence to support the assumption that 

 the carpogonial branch develops by the repeated division of the 

 terminal cell. In several cases the nucleus of this cell is consider- 

 ably enlarged and is evidently just preparing for division (fig. 28). 

 The chromatophores are much more openly clathrate in the 5-celled 

 carpogonial branch than in the younger branches (fig. 29). One 

 branch was observed in which the fifth cell, the terminal cell, was 

 binucleate (fig. 30). Each cell in a carpogonial branch until it 

 has reached the 5- or 6-celled stage generally contains one chromato- 

 phore. The one chromatophore then divides into a number of 

 small parts which are connected by strands of cytoplasm (fig. 31). 

 The structure and the arrangement of the cytoplasm and chroma- 

 tophores at this stage appear to be very similar to those in the 

 tetrasporangium and the tetraspores. The fate of most of the chro- 

 matophores in the cells of the carpogonial branch appears to be the 

 same as that of those in the spermatium mother cells. The chroma- 

 tophores disappear and at the same time the granular cytoplasmic 

 contents of the cells increase. The protoplasm in the chromato- 

 phores is apparently used to form a part of the granular cytoplasm. 

 There are generally present 2 or 3 chromatophores in each of the 

 3 or 4 basal cells, even after fertilization, when the sporogenous 

 filaments are being formed (fig. 42). These chromatophores are 

 hollow ellipsoids, like those in the tetraspores, but unlike the latter 

 generally show no sign of being clathrate. 



A large number of carpogonial branches were observed which 

 bore short stumps or fairly long pieces of trichogynes (figs. 32-38). 

 These trichogynes could often be traced almost to the surface of 

 the thallus (figs. 35,37). Other trichogynes were found which pro- 

 jected beyond the surface of the thallus and which could be traced 

 back toward carpogonial branches (figs. 39, 40). Although no 

 carpogonial branch was found in which the trichogyne could be 

 traced from the carpogonium out beyond the surface of the thallus, 



