E. RAY LANKESTER, ON GREGARINID. 87 
little, but, nevertheless, has proved beyond doubt that the 
nematodes of the earthworm are developed from eggs, whence 
they emerge, not as Gregarie, but as true nematodes. 
The transformation of two Gregarine, after a process of en- 
eystation, into navicula-like bodies, has already been described 
by Bruch; but Lieberkiihn has more fully illustrated the 
changes which go on, and has endeavoured to trace the 
existence of the Pseudo-navicule after they have been expelled 
from the cyst. In the perivisceral cavity of the earthworm 
he found large numbers of small corpuscles, exhibiting 
Ameeba-like movements and likewise Pseudo-navicule, con- 
taining granules, formed from encysted Gregarine. He 
imagines that these latter bodies burst, and that their con- 
tained granules develope into the Ameebiform bodies which 
subsequently become Gregarine. In the same year* M. 
Lieberktihn published another paper, describing his further 
researches among the psorosperms of fish, in which he adopts 
the same view, that the Amcebiform corpuscles of the blood 
of fish are Gregarine. Few physiologists will feel disposed to 
agree with M. Lieberkiihn, in considering these bodies as 
parasites. Dr. Williams, of Swansea,t has described a great 
variety of forms, from Mollusca, Crustacea, and Annelida, 
remarking that they are characteristic of the fluids of inverte- 
brata. M. Milne Edwards, in his ‘ Lecon sur Physiologie,’ 
speaking of the white corpuscles of the blood, makes the 
following remarks upon Lieberkiihn’s proposition :—“ Enfin 
M. Lieberkiihn qui vient de faire une étude attentive de ces 
corps, croit méme de voir les considérer comme étant des ani- 
malcules parasites et les assimiler aux Amibes, petits infusoires 
dont l’intestin de divers animaux est parfois infesté; mais les 
arguments en faveur de cet opinion ne me paraissent pas assez 
solides, pourque dans l’état de la science, on puisse l’adopter ; 
et lors méme que quelques uns de ces corps seraient réellement 
de la nature des animaux sarcodaires,il ne faudrait pas conclure 
que tous les corpuscles incolores et granules du sang sont des 
parasites, car il parait evident, comme nous le verrons par 
suite, que ce sont en générale, bien réellement des produits 
de Vorganisme” (pp. 73, 74, vol. i). Also further on, in 
speaking of these “corpuscles de plasme”’ in invertebrata, he 
adds, ‘Ce phénoméne remarquable a été fort bien observé par 
M.Wharton Jones, aussi que par M. Williams, et par quelques 
autres physiologistes * * * * et il est si frequent ici 
que je ne saurais l’attribuer 4 l’existence d’Amibes parasites 
comme le fait M. Lieberkiihn” (p. 103, vol. 1). The 
* Miiller’s ‘ Archiv,’ 1854. 
+ ‘Proce. Royal Soe.,’ 1852. 
