THE BEGINNINGS OF LIFE. 199 



for a longer time stationary in the same situation. It 

 devours no more food, and sends out only short projec- 

 tions. When the central mass has attained its maxi- 

 mum size, and when no further trace of granules re- 

 mains in its glutinous body-substance, the Amoeba 

 contracts and becomes rounded, by collecting its out- 

 lying portions around the enclosed and altered granular 

 mass. Then, after a time, suddenly and with the rapidity 

 of lightning, the germ-mass breaks up and disappears, 

 shooting out around the space which it had previously 

 occupied myriads of oblong particles, each furnished 

 with a thread-like flagellum 1 . These dart about in the 

 water and closely resemble very minute Astasl<e. 



In the great majority of animals ova are produced 

 from germs arising either (a) in the upper part or 

 blind extremity of an ovarian tube, or else () in the 

 midst of the stroma of a more or less solid organ, 

 called an ovary, where each is invariably lodged within 

 an c ovisac 3 or so-called Graafian follicle. The best 

 examples of the first mode of origin of ova are to be 

 met with amongst Nematoids and Insects; whilst in 

 Birds and throughout the Mammalian series, on the 



1 In the case of Conferva area, however, the granules, instead of 

 separating from one another at once and with such rapidity, are stated 

 by Agardh to detach themselves one by one from the spherical heap of 

 granules similarly formed. Then, however, they also move about with 

 great rapidity. The suddenness of the dispersion reminds one of the 

 phenomena of ' diffiuence ' which have been observed in certain Amoebae 

 and Ciliated Infusoria, and to which, indeed, Nicolet calls the attention 

 of his readers. 



