4 BRITISH FRESHWATER RHIZOPODA. 



usually visible ; the pseudopodia filose and dichoto- 

 mously branched. 



Owing to the transparency of the tests in all species 

 of this genus, the processes of division, encystment, 

 etc., can be readily followed ; reserve scales are fre- 

 quently observed within the tests of all the species 

 except E. cristata which accumulates them around the 

 exterior of the aperture. 



The process of encystment and of the development 

 of the cyst in Euglypha acanthophora (alveolata) has 

 recently been described and illustrated in detail by 

 Popoff* up to the liberation of the " swarm spores " or 

 gametes ; these are isogametes, and from the conjuga- 

 tion of two of them a small amoeboid form results, the 

 further development of which has not been followed. 



Large tests of about double the average linear 

 dimensions are occasionally seen ; these according to 

 Penard are maturation or " double encystment " tests, 

 and result from the plastogomy of two individuals. 



The processes of conjugation and fission have been 

 alluded to in Vol. I, pp. 22-25. During division, the 

 nucleus may divide by a process of nearly normal 

 mitosis or occasionally by the more simple method of 

 fission ; perhaps it is after the latter process that a 

 moiety of the nucleus and the reserve scales are some- 

 times discarded as described in Vol. I, p. 23. 



With reference to the spherical bodies (diameter 

 8-1 JJL) so often found in Euglypha and other tests, 

 having the appearance of spores, and the presence of 

 so-called reproductive bodies often seen in the plasma, 

 it should be borne in mind that many kinds of parasites 

 infest the Rhizopoda, and that until the life-histories 

 of these various bodies have been worked out it would 

 be premature to hazard any definite pronouncement on 

 the subject. Some of the so-called "reproductive 

 bodies" no doubt represent granules of excretion. 



The plasma of the Englyplise can be readily examined 



* ' Archiv fur Protist.,' vol. xxv, pt. 1, 1912. 



