630 MICKOSCOPIC FORMS OF VEGETABLE LIFE-THALLOPHYTES 



other species of Fucua, imbedded in the frond, and the ' berries ' of 

 Sargassum bacciferum, the 'gulf- weed' of the Atlantic, which are 

 elevated on pedicels above the surface of the water. The whole 

 substance of the Fucacece, including the reproductive organs, i 

 coloured brown by fuco-xanthin, the same pigment as that which n 

 found in the Phceosporece. 



Among the Floridese, or red seaweeds, also, we find various 

 simple but most beautiful forms, which connect this group with the 

 lower algae, especially with the family Coleochcetacece ; such delicate 

 feathery or leaf-like fronds belong for the most part to the family 

 Ceramiacece, some members of which are found upon every part of 



Fig. 472. Arrangement of tetraspores in Carpocaulon mediterraneum : A, entire 

 plant; B, longitudinal section of spore-bearing branch. (N.B. "Where only three 

 tetraspores are seen, it is merely because the fourth did not happen to be so placed 

 as to be seen at the same view.) 



our coasts, attached either to rocks or stones or to larger algae, and 

 often themselves affording an attachment to zoophytes and polyzoa. 

 They chiefly live in deeper water than the other seaweeds, and 

 their richest tints are only exhibited when they grow under the 

 shade of projecting rocks or of larger dark-coloured algae. Hence, 

 in growing them artificially in aquaria, it is requisite to protect 

 them from an excess of light, since otherwise they become unhealthy. 

 Various species of the genera Ceramium, Griffithsia, Callithamnion, 

 and Ptilota are extremely beautiful objects for low powers when 

 mounted in glycerin jelly. In many of them the phenomenon to 

 which we have previously referred under the name of ' continuity of 

 protoplasm ' is very beautifully exhibited. The colour of the red 



