542 Transactions of the Society. 



liquid (Fig. 18). The young Notommata sometimes make their 

 escape through this opening. The proof that the parasites do not 

 themselves make the opening, as might he supposed, is that the 

 capsules are often found perforated whilst still enclosing unhatched 

 eggs. 



The filaments at the hase of the capsules (Figs. 16, 17, 6 a) are 

 formed in the same way. In this case also openings are sometimes 

 formed (Fig. 18, x") for the escape of the animal. Sometimes the 

 antheridian tube itself at the base of the capsule, with its open 

 extremity, serves as the exit (Fig. 17, r a). 



Sometimes the young animals penetrate into the principal 

 filament and reach another capsule which has an opening by which 

 they can pass out. Their passage is, however, sometimes barred 

 by the false septa (Figs. 15, 16, 18, /c), which are formed with 

 such facility in the filaments of Vaucheria wherever there is a 

 lesion, a septum of cellulose on either side isolating the part 

 aflected and preventing it spreading to the sound parts.* 



Gradually the capsule becomes empty of animalculae, and 

 various Infusoria invade it and complete the destruction of the 

 green matter. 



The young Notommata move about very quickly when free in 

 the water. They take no food during this period of free life, and 

 soon return to the plant, never again to quit it. This re-entrance 

 is efiected through the various openings of the capsules which I 

 have just described, from which they pass into the young green 

 branches. Thus is explained their introduction into the tubes of 

 Vaucheria, which was an enigma to all observers, with the excep- 

 tion of Dr. Magnus. 



I will now speak of the destiny of the winter eggs. As we 

 have seen already, they began to be laid in April, at first with 

 summer eggs, then alone. About the middle of May, the laying 

 of summer eggs had ceased, and the capsules contained only winter 

 eggs. They were in much greater number than the summer eggs. 

 In spite of all my care the Vaucheria died, but the eggs remained 

 unaltered in the capsules, presenting no sign of development during 

 the summer, autumn, and first half of winter. Unfortunately my 

 observations were interrupted, and at the end of March I found all 

 the eggs had hatched. This hatching must have taken place at 

 the end of winter or beginning of spring, and the young had 

 probably perished from want of food, as I found none in the 

 water. 



This interesting animalcule is not the only species of the genus 

 Notommata parasitic on an Alga. Ehrenberg has made us 



* See Hofmeister, ' Handbucb der Physiol. Bot.,' vol. i. p. 76, and Hanstein, 

 ' Lebensfahigkeit der Vaucheriazellen ('Niederrh. Ges.,' Sitz. V., 4 Nov. 1872, 

 and 'Bot. Zeir.,' 1873, p. 697. 



