138 
J. D. SIDDALL. 
placed by one very large hyaline vesicle containing denser 
matters within it. Watched for some time this vesicle was 
seen to travel towards and ultimately protrude beyond the 
protoplasm of the Amoeba, then rupture and discharge its 
contents into the surrounding water, wherein they appeared 
as bright spots held together by a viscid substance, the 
vesicle afterwards collapsing and disappearing entirely. From 
one of the two masses a thin layer of protoplasm is still 
(March, 1880) extended, immersed in which are a number 
of very transparent and much enlarged nucleated granules, 
of tolerably regular form. In the larger of these a general 
slow movement of the contents is discernible, and some 
which became detached afterwards put out Actinophrys-X^^ 
pseudopodia, as represented in PI. XV, fig. 13, ajh,c. These 
new forms generally develop a nucleus and small internal 
contractile vesicle, and in one instance a specimen divided 
into three distinct individuals. Like the Amoebse, most of 
these have now become quiescent, and the tv/o masses of 
sarcode have become smaller and paler in colour, in con- 
sequence of the detachment of particles from them. 
From the foregoing account it will be gathered that little 
beyond the dissolution oiShephear della into amoeboid particles 
has yet been quite satisfactorily traced. No attempt at 
fission, encystation, or anything approaching to either, and 
no development of special reproductive bodies, unless we 
accept as such the minute spheroid drawn on PI. XV, fig. 15, 
having yet been observed. The loss of the specimen pos- 
sessing three nuclei was a matter of much regret, as I had 
hoped, judging from what has been noticed in other simple 
organisms having more than one nucleus, that it might ul- 
timately divide into three distinct individuals, and by so 
doing give conclusive evidence of at least one process of 
reproduction. As it at present stands, the life history of 
Shepheardella may be looked upon as a chain, a few links of 
which are here presented, the major portion being still 
missing. 
The similarity of Shepheardella, in point of external form, 
with the Gregarina gigantea of M. Van Beneden, has 
attracted my attention ; but as it is not known that the Gre~ 
garinidoe, except in the very earliest stages of their existence, 
resemble the Rhizopoda in possessing the power of extend- 
ing pseudopodia, the idea which presented itself that the 
animal I have described might possibly be only one stage of 
some large parasitic creature of this class, has not yet been 
seriously followed up. Should there be anything in its life 
history to verify or controvert this superficial resemblance 
