30fi M. A. Schneider on Oplnyocystis Butsclilii. 



real conjugation, exactly like that of the Gregarinie and 

 Monocystidea. This is why, if we admit the plasmodial 

 significance of the plurinucleate amoeboid stages, it would be 

 all over with conjugation in all this history ; but nothing is 

 impossible. It may also be that the plurinucleate stages 

 serve to multiply the parasite in place by division or gemma- 

 tion, and encystment only to propagate it externally from one 

 individual to another ; and if I were compelled to choose 

 among all the hypotheses, it is upon this last that I should 

 rest. Then the evolutive cycle would be a cycle with alter- 

 nation of generations*. 



The stage shown in fig. 27 I regard as one of those which 

 precede conjugation. The body is spherical on the whole, 

 sometimes without, but most frequently with fine processes 

 over the whole smface. Fig. 16, if I am not mistaken, re- 

 presents the very act of conjugation, for each individual still 

 bears a tuft of filiform expansions at one of its extremities. 

 Its resemblance to Zygocystis is striking. If we imagine 

 these processes withdrawn we shall have fig. 18. The junc- 

 tion is effected ; the two spheres are in contact by an extended 

 plane, which, gaining a little more in breadth, will soon trans- 

 form the pair into a cylinder with convex ends (fig. 28). 

 This cylinder secretes a wall marked with an equatorial line 

 following the line of adhesion of the conjugated individuals, 

 and the encystment is completed. This equatorial line of the 

 wall is a line of weaker resistance, along which will be 

 effected the dehiscence of the envelope of the cyst. This re- 

 minds us of the similar line in the cysts of certain Gregarinae, 

 among others Trichorhynchus pulcher^ . 



When we render transparent the recently formed cyst after 

 staining the nuclei, we find two nuclei, one in each hemisphere, 

 as I have already stated, and as is shown in fig. 25. These 

 nuclei are of the same size as in the spherical individuals (fig. 



* Since writing these lines I have met with a new Ophryocystis in 

 specimens of Akis, some of them (^Akis alyeriana) from Oran, the others 

 (Akis acumitiata) from Malaga, brought back by my friend M. Francois 

 from a journey in Algeria and Spain. This species is more easy to 

 study. The drawngs that I possess seem to me to establish that the 

 plurinucleate sarcodic masses really divide to produce the specimens with 

 a single nucleus destined to conjugate. I have seen cases in which 

 there was a rosette of four, six, eight, &c. individuals with single nucleus, 

 united to a centre as if by a loug process, and diverging from each other 

 by the granular mass which contains the nucleus. I recommend these 

 Akides to those who wish to review and complete this investigation. I 

 shall be obliged to such persons as do not themselves take any interest in 

 these researches if they will be kind enough to send me a little box of 

 those insects. 



t A. Sclineider, " Secoudi' C'onlributioa a IVHude dcs (Jregarines," 

 Archives de Znol. J'^xjier. I'icc. tomo x. p. 123. 



