1864. | Zoology and Physiology. 175 
as those peculiar to the colourless specimens, but with the difference 
that they were all provided with a cilium (perhaps two); most were 
fixed and retained their globular form; others swam about by means 
of their cilium; many of the fixed globular forms altered their shape 
by becoming polymorphic; and some lost their cilium and became 
altogether reptant and amcebous. There can be little doubt that these 
Amoebee are the young brood of Difflugia pyriformis. Thus the cycle 
of generative development in this Rhizopod by “granulation of the 
nucleus” is so far completed. It is probably the same as in Amaba 
princeps. The development of the young Amba into adult testaceous 
Diflugice has not yet, however, been observed. 
We should hardly be prepared for psychical development in these 
minute masses of sarcode, nevertheless Mr. Carter’s observations of 
Aithalium and Actinophrys render it probable that certain manifesta- 
tions of instinct are occasionally evinced by them, of the same kind as 
those in the higher animals. On one occasion, for example, Mr. Carter 
observed an Actinophrys station itself close to a ripe spore-cell of 
Pythium, which was situated upon a filament of Spirogyra, and as the 
young ciliated germs issued forth, one after another, from the dehiscent 
spore-cell, the Actinophrys remained by it, and caught every one of 
them even to the last, when it retired to another part of the field, as if 
instinctively conscious that there was nothing more to be got at the 
old place. As, however, these lowest forms of life appear to have but 
one object, and that the attainment of food, we cannot be so much 
surprised if they are provided with sufficient discrimination to be aware 
when they are receiving it, and when the supply has ceased. Indeed 
their whole instinctive development is concentrated upon that important 
end. 
