184 Objects for the Microscope. 



culosus, which is a dioecious plant, the antherozoides meet 

 the spores in the water directly after they issue from the 

 receptacle. 



To observe this, take an olive-green receptacle, which is 

 the female, and set free a few pores in a drop of sea-water 

 in a shallow cell ; then liberate a few ripe filaments from 

 an orange-yellow receptacle, which will contain the anthe- 

 rozoides, and the whole process of fertilisation may be 

 watched with a power of 250 diameters. 



Then, if you further wish to prove the subsequent pro- 

 cess of germination, a little care and patience will enable 

 these very spores to grow from the cell of what is called a 

 "growing slide," or even in a tumbler of water, taking 

 precautions to keep the water fresh and still, by drawing it 

 off with a siphon, and renewing it daily in the same gentle 

 way. 



The fructification of the Rhodospermese, or red sea- 

 weeds, has not yet been so thoroughly investigated, and 

 the varied forms of the spore-cases will be the chief beauty 

 as well as value of the following preparations. 



CALLITHAMNION. 



There are twenty-five species of this plant, and most of 

 them are common on the shores of Great Britain ; its name 

 is derived from two Greek words, signifying " beautiful 

 little shrub," and it is very beautiful, with a rosy or brown- 

 ish-red frond, or rather filament, jointed and branching, 

 bearing two kinds of fructification : 



1. External tetraspores seated upon the branches. 



2. Roundish or lobed berry-like receptacles, called 

 favellaB, seated on the main branches, and containing many 

 spores. 



Callithamnion delights in mud-covered rocks. C. roseum 

 is found at Torquay; also C. gradllimum growing along 

 the mud-covered base of the harbour. In fact, the collector 

 must often content himself with a handful of mud, showing 

 merely a few red filaments, and then on washing these 

 carefully he will find not only one, but perhaps many 

 species of this lovely Sea-weed. 



