i 9 1 7] DUNN—DUMONTIA 437 



few cells in the lower layers of the holdfast, contain but one chroma- 

 tophore. The chroma tophore is a clathrate hollow ellipsoid lying 

 just inside the cell wall (fig. 12). It is similar to the peripheral 

 portion of the chromatophore figured by Wolfe (19) in Nemalion. 

 The chromatophore in some cells was seen to be enveloped by a 

 thin layer of cytoplasm in the form of a coarse net. This cyto- 

 plasmic envelope, although not always visible, was undoubtedly 

 present in all the cells. 



Intercellular connections, such as are characteristic of the 

 Florideae, are present between all the vegetative cells and all the 

 sexual reproductive cells, including the carpospores, until they are 

 almost mature. At each intercellular connection there are two 

 similar disks joined by an apparently homogeneous strand of 

 cytoplasm. The cytoplasm appears to penetrate these disks, but 

 the matter has not been thoroughly investigated. The disks 

 stain readily with hematoxylin, and in some cells appear to be 

 composed of granules (fig. 13). One case was seen in which a 

 strand of cytoplasm 4 ll wide connects two carpospores 2 2 ix in 

 diameter (fig. 14). In this strand of cytoplasm are several granules 

 having an average length of o . 7 lx. These granules stain with the 

 same intensity as the disks. It is probable that these granules 

 would collect together to form the two disks when the strand of 

 cytoplasm has assumed its normal size. Trichomes are found on 

 all parts of the surface of the thallus. They seem to be most 

 numerous at the base of the frond. They are present on the male, 

 female, and tetrasporic plants. The trichomes are very abundant 

 on the young plants collected in April. 



SPERMATIA 



Definition. — If the following discussion is to be intelligible, it 

 will be necessary to define the terms which will be used in the 

 description of the male reproductive organs. Those cells which are 

 analogous to the sperms of the green and brown algae will be 

 designated as spermatia. Yamanouchi (20), writing of Poly- 

 siphonia, calls these cells sperms, but " spermatia" is the term 

 which has been most widely used by workers on the red algae and 

 is therefore to be preferred. 



