THE PATH OF EVOLUTION 



tinne on their course. Others seek each other, 

 remain side by side, and their gelatinous bodies melt 

 into each other their increased size and duplication 

 of the number of their tentacular cilia alone indicat- 

 ing their former separate existence. Those that avoid 

 each other have escaped from the same enveloping cell. 

 Those that seek each other and blend into each other 

 are from the chamber cells of different individuals. 

 This is the procedure with the Ulothrix (" Curly hair," 

 a fresh water Alpine Alga), and is the simplest con- 

 ceivable form of fertilization among plants. In other 

 Alga3 (the Spirogyra, for instance), when the cells of 

 different filaments are nearly in contact, they pro- 

 trude their respective walls towards each other. The 

 latter, which in these organisms are always soft and 

 plastic, dissolve when the protrusions meet. The plas- 

 modium in the opposite cells in each now gathered 

 into globules pass from one into the other, and, 

 uniting, form a single globule. This now fills with 

 granules, and when ripe escapes through the side of 

 the cell. Ultimately this globule bursts, liberating 

 its contents; each granule, after its migratory exist- 

 ence, as before described, starts a new life, and by 

 subdivision of its cell walls grows and forms a new 

 plant like its parent. No difference can be observed 

 in the appearance of the plasmodic globules before 

 their junction, though without doubt a difference in 



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