Objects for the Microscope. 183 



called nemathecia, or warts, concealed under leafy processes 

 composed of delicate mpniliform or bead-like filaments. 



Rhodymenia gives an example of embedded tubercles 

 containing spores called coccidia. 



Nitophylmm is spotted with son', each of which contains 

 a number of tetraspores. 



Polysiphonia fastigiata abounds with antheridia at the 

 tip of its filaments amongst spiral fibres. 



The fructification of the highest order is that of Fucus 

 serratus and platycarpus, which should be examined fresh 

 from the plant, and is seen in perfection between the 

 months of December and April. It has a truly sexual cha- 

 racter, and as the receptacles of this Fucus contain both 

 the " sperm-cells " and the " germ-cells," it is considered 

 an hermaphrodite plant. 



In the common Fucus vesiculosus (Bladder-wrack) the 

 receptacles containing antheridia are found on one plant, 

 and those containing sporangia on a separate individual ; 

 it is best, therefore, to obtain the F. platycarpus or serratus, 

 which latter is found abundantly at half-tide, and easily 

 recognised by the toothed edges of its frond, when both 

 organs are observable in the same plant. 



Choose a mature receptacle, which maybe known by its 

 discharging little gelatinous masses adhering round its 

 orifice. Make a section through it, and you will see a 

 globular cavity lined with filaments, some of which project 

 through the pore. These filaments are jointed, or rather 

 are composed of cells containing what are called anthero- 

 zoides ; these are yellow dots with two long thread-like 

 appendages, which, when liberated by the breaking of the 

 cell, have a spontaneous and rapid motion, and they imme- 

 diately swarm around the sporangia, and fecundate them. 

 The sporangia are pear-shaped bodies lying amongst these 

 filaments near the walls of the cavity, and they are the 

 parent cells of the germ cells, which produce the spores or 

 seeds. Each of these sporangia gives forth a cluster of 

 eight cells, and are therefore also called octospores. 



In the hermaphrodite fuci the spores do not leave the 

 receptacle until after their fecundation ; but in Fucus vesi- 



