LIFE HISTORIES OF THE PROTOZOA. 429 > 
2. Lepomonera, which become encysted and protected by a case, 
as in the genera Protomonas, Protomyxa, Vampyrella and Myxas- 
trum. 
The simplest form of all is Protameeba, which is a simple mass 
of protoplasm without vacuoles (little cavities), which protrudes 
simple processes (pseudopodia) not ramifying or forming a net- 
work. Protogenes differs in protruding ramifying and anastomo- 
sing gelatinous threads, while Myxodictyum, the most complicated 
form, is made up of several simple Actinophrys-like bodies, whose 
pseudopodia branch out and interlace, forming a net. 
The simplest form of life known to us is Bathybius, a mass of 
albuminous jelly. If the theory of spontaneous generation should 
ever prove true we could imagine that the first living form would 
be like this organism, a mass of jelly, utterly structureless, and 
yet capable of motion (irritability), of taking food and digesting 
it, and of reproducing its species, and thus having an individu- 
ality. 
Bathybius is conséquently the most interesting organism (should 
it be proved to be such,) known except man. It cannot be said to 
be distinctively either animal or plant, though it has been studied 
chiefly by zoologists, and intergrades with the higher Moners, 
which seem to pass by the sum of their characters into the 
bæ and higher Rhizopods rather than into the Protophytes. But _ 
in the Moners we find a group of uncertain forms from which the 
plant and animal kingdoms diverge, and from which, consequently, 
they may have taken their origin. The Moners stand in the same 
relation to the whole world of organized beings that the egg does 
to the animal kingdom. All animals exist first in the form of nu- 
cleated cells, while the primitive form of plants and animals col- 
lectively, is a simple non-nucleated mass of protoplasm like Bathy- 
bius, and for these forms, neither distinctively plant nor animal, 
Heeckel’s term Protista is a convenient one for provisional use. 
Pathybina was first discovered by Prof. Wyville Thompson in 
1869 in dredging at a depth of 2435 fathoms at the mouth of the 
Bay of Biscay. He describes it as a “soft, gelatinous, organic 
matter, enough to give a slight viscosity to the mud of the surface 
layer.” Thompson also adds that if a “little of the mud in which 
this viscid condition is most marked be placed in a drop of sea 
water under the microscope, we can usually see, after a time, an 
irregular net-work of matter resembling white of eggs, distin- 
