Species o/'Coccidium infesting Perichasta. 435 



Micropyle. — At one end of the cyst in all individuals is a 

 structure which I identify with what has been termed by 

 Waldenberg* (its discoverer) and Leuckartf a " micropyle." 

 The micropyle, however, in the Goccidiuni of Perichmta 

 armata is rather different iVom that of G. oviforme. 



In C. oviforme the micropyle is stated to be an extremely 

 fine pore and to be situated at one pole of the cyst. 



Schneider % has described a structure in the cyst-raembrane 

 of Orthospora propria which appears to correspond to the 

 micropyle ; it does not, however, appear from Schneider's 

 description to be a pore, but a slight bulging of the cyst- wall 

 inwards at one extremity of the cyst. 



Biitschli considers that probably this " stigma " upon the 

 cyst of Ortliospora corresponds to the so-called micropyle of 

 Coccidium. I observed in one specimen of Coecidium (fig. 10) 

 a slight thickening at one end of the cyst which projected 

 into the interior, and which agrees very closely with 

 Schneider's figures § of the " stigma " of Orthospora ; but I 

 never noticed any such relation between the '' stigma " and 

 the cell-contents as he has figured || and described. 



In Coccidium from Perichceta armata there is always, with 

 very rare exceptions, such as that just mentioned, a micropyle 

 Avhich differs considerably from that of G. oviforme or of 

 Ortliospora. In the first place {cf figs. 1, 2, 3, &c.) its position 

 is not constant; it may be situated (fig. 1) at one pole, but as 

 frequently it is placed at one side more (fig. 15) or less (fig. 2) 

 remote from the pole. The appearance of this structure, 

 which I have termed a micropyle because that is the generally 

 received term, is such that I am inclined to agree with 

 Schneider in believing it not to be a perforation ot the cyst- 

 membrane at all. My specimens of this Goccidiuni are 

 mounted in glycerine, so that their position can be changed 

 at will by pressing with a needle upon the cover-glass. 

 When the position of the Goccidium upon the slide is such 

 that the micropyle is seen in profile it presents the appear- 

 ances represented in figs. 2, 8, 9, 15. These figures illustrate 

 what the preparations seem to teach, viz. that the so-called 

 micropyle is simply a bulging in of the cuticle, perhaps 

 due to a separation of part of the internal cuticular lamella 



* "Zur Entwickelungsgeschichte der PsorospermieD," Arch, pathol. 

 Anat. Bd. xl. (18(i7) p. 435. 



t Loc. cit. 



X '* Sur les Psorospermes oviformes ou Coccidies" Arch. Zool. Exp. t ix. 

 (1881) p. 387. 



§ Loc. cit. pi. xxii. fig. 4 h, and figs. 5, 0, 7, 8, 10. 



II Loc, cit. pi. xxii. iig. i c. 



31* 



