584 E. RAY LANKESTER. 



'Archives de Zoologie experimentale/ 1898. In Fig. 12 we 

 have reproduced (from Mesnil) his drawings. The sperma- 

 tozoa are seen to be biflagellate, having a flagellum at each 

 end of the fusiform body. The modes in which these flagella 

 may be carried and exercised is shown in the drawings. 

 Compare these with the active filaments pi'oduced by the 

 male gametocyte of Haemamoeba (Hgemomenas) which are 

 shown in PL 30, figs. 48 and 50. 



The first discovery of spermatozoa as the product of a 

 Coccidian cell was made by Simond ('Ann. de I'lnstitut 

 Pasteur/ 1897. We reproduce here (Fig. 13) one of his 

 drawings. Simond made his discovery in the typical well- 

 known parasite of the epithelial cells of the rabbit's intestine 

 and liver — the Coccidium oviforme. He showed that 

 whilst Coccidium oviforme very generally breaks up 

 into sporocyteSj which enter uninfected epithelial cells and 

 develop into full-sized Coccidia directly, yet the cell indi- 

 viduals of Coccidium oviforme also can and do under 

 certain circumstances become gametocytes, instead of break- 

 ing up into sporocytes; some developing a micropyle and 

 becoming each a single ovum or macrogamete, whilst others 

 (lying all the time within an epithelial cell of the rabbit) 

 give rise to a crop of spermatozoa or microgametes, resting 

 on a residual mass or blastophore just as in Lumbricus. The 

 crop of spermatozoa and the blastophore of Coccidium 

 oviforme is shown in the woodcut Fig. 13. 



The existence within the Protozoa of the form and mode 

 of development of the male microgametes now so long familiar 

 to us in higher animals, where they are called " spermatozoa," 

 is one of the most striking results of the recent researches 

 on Sporozoa. It is all the more curious when we remember 

 that these cell parasites, such as Coccidium oviforme and 

 Hgemomenas prsecox, are amongst the most minute of 

 the characteristically minute Protozoa. 



I will venture on one farther comparison and comment 

 in regard to the life-history of Haemomenas praecox as 

 described by Surgeon-Major Ross. Ross discovered the 



