THE ALGJE 



141 



globular spermatium, naked at first, but later developing a delicate membrane. 

 This comes in contact with the trichogyne, and its contents pass into the carpo- 

 gonium, the nucleus passing into that of the carpogonial cell. The fertilized 

 cell does not develop into a spore, as in the other Algse, but begins to grow and 

 divide, forming a large mass of short branches, whose end-cells become the 

 spores, the whole structure being known as the " Spore-fruit," or Sporocarp. 

 The spore-mass may in some forms be surrounded by a loose envelope of branches 

 developed from the cells in the vicinity of the carpogonium. 



FIG. 110. A, Rhabdonia tenera (natural size) ; sp, cystocarps. B, Gigartina 

 spinosa, plant with cystocarps, reduced about one-half. C, Endocladia vernicata, 

 procarp; aux, auxiliary cell; t, trichogyne. (After HAUPTFLBISCH.) 



Order II. Gigartinales 



The Gigartinales are mostly Algae of comparatively large size and 

 coarse texture. Many of them, e.g. Chondrus crisptts, the "Irish 

 Moss," and various species of Gigartina (Fig. 110, B), grow attached 

 to rocks where they are exposed to the surf. They are very tough 

 and cartilaginous in texture, due to the large development of the 

 gelatinous intercellular substance. Owing to this some of them are 

 utilized to some extent for food. The tetraspores are usually buried 

 in the thallus. The antheridia form patches of small superficial 

 cells, each of which gives rise to a spermatium. 



