242 
RESEARCHES on the DEVELOPMENT of the GREGARINE. By 
Epovarp VAN BrENneEDEN, D. Sc., Professor of Zoology 
and Comparative Anatomy in the University of Liege. 
Tue development of the Gregarinz has been the object of 
a great number of investigations, and has exercised the saga- 
city of a number of distinguished observers. Nevertheless, 
at the present time it is not fully elucidated. The relation 
existing between the Gregarine and the psorospermic vesicles 
was first perceived by von Siebold,' Henle,? and von Frant- 
zius,® and definitely demonstrated by the beautiful researches 
of Stein,* K6lliker,® and Lieberkiihn.® It appears well es- 
tablished that, although sometimes two Gregarine conjugate, 
fusing subsequently into a common mass in one and the same 
cyst (Stein), yet the conjugation does not necessarily precede 
the encystment, and often a single Gregarine transforms 
itself into a vesicle (Bruch, Frantzius, Leuckart, and myself), 
to give birth, quite as in the first case, to a great nuinber of 
psorosperms. There are certain Gregarine in which the con- 
jugation is never observed; others which one finds always 
apposed (Zygocystis, Didymophyes), either by their analo- 
gous extremities, or by their opposite extremities (Grega- 
rine). 
The granular contents of the cysts may divide, and the 
capsule common to the two globes thus produced may disinte- 
grate and become transformed into a viscid and granular sub- 
stance, after a new membrane has developed round each of the 
new globes of the second generation. These again may divide 
in their turn, and there will be thus presented series of cysts. 
enclosing some a single granular mass, others two similar 
masses enclosed in a single capsule. All these cysts, which 
may be compared as far as their mode of multiplication is 
concerned, to the corpuscles of cartilage, are held in suspen- 
sion in a common fundamental material resulting from the 
disintegration of the original capsules (Edouard Van Be- 
neden).’ In this manner we can explain the presence of 
those linear series of cysts which are met with in the thick- 
1 Von Siebold, ‘ Beitrage zur Geschichte wirbelosser Thiere,’ 1839, p. 69. 
2 Henle, ‘ Miiller’s Archiv,’ 1845, p. 574. 
3 Von Frantzius, “ Observationes quoedam de Gregarinis,” Berol, 1848. 
4 Stein, ‘ Miiller’s Archiv,’ 1848, p. 204. 
5 Kolliker, ‘ Zeitschrift fur wiss. Zool.,’ t. i, p. 1. 
® N. Lieberkiihn, “Evolution des Gregarines,’’ ‘Mem. Acad. Roy. de 
Belg.,’ c. Xxvi. 
7 Edouard Van Beneden, ‘ Quarterly Journal of Microsc. Science,’ New 
Series, No. XXXVII, 1870. 
