582 



E. RAY LANKESTER. 



form as a series of nucleated outgrowtlis of the original cell, 

 leaving a non-nucleated " blastophore " or residual mass, as 

 in Haemomeuas, PI. 30, fig. 48. In the lower three figures 

 (Figs. 4, 5, 6) we have an egg-cell which is undergoing 

 fertilisation. Three free spermatozoa are seen attempting to 

 effect a junction with it. These figures are after the draw- 

 ings and description of Siedlecki in 'Annales de I'Institut 

 Pasteur,' 1898, and are copied from Mesnil, 'Revue generale 

 des Sciences,' March 30th, 1899. 



The development of the spermatozoa or microgametes of a 



Figs. 1 — 6. — Development of microgametes or spermatozoa and fertilisation 

 of tlie Coccidian Benedenia octopiana. After Siedlecki, from 

 Mesnil. 



complex multicellular animal may be compared with what 

 occurs in the unicellular Benedenia and Hasmomenas. Our 

 Figs. 7 to 11 show the development of the spermatozoa of 

 the earthworm ; they are reproduced from Blomfield's paper 

 in vol. XX of this Journal (1880). It will be observed that 

 iu the earthworm, as in the Coccidian and the Haemamoeba, 

 the spermatozoids form by a centifrngal movement of the 



