114 TlMEHRI. 
kind of reticulate Animalcule observed, may consist ot 
one chamber or of several. When there are several 
chambers, they are generally arranged either in a line, 
like a row of beads, or in a spiral, like the coils of the 
shell of a nautilus or snail. In many reticulate Animal- 
cules, no distinft shell is to be found, but the organism 
forms a covering composed of cemented foreign 
matter, like sand grains, sponge spicules, &c. It 
must be particularly noticed, however, that though 
the shell may be composed of many chambers, and the 
chambers filled with the protoplasmic substance, yet the 
whole consists of one cell. The body substance is con- 
stri6led, but not entirely divided off so as to form inde- 
pendent parts ; the whole consists of an original cell, 
around which several partial buds have developed, w 7 hich 
are not distinct from, but are intimate parts of, this cell. 
Owing to the minute holes ox foramina which generally 
pierce the shell in all directions, these reticulate Animal- 
cules are classed together as the Forarninifera. They 
are, almost without exception, marine organisms ; and, 
though found plentifully in the deep sea, are essentially 
characteristic of the surface layers of the tropical seas 
and oceans. In such areas one form, technically known 
as Globigerina, is extremely abundant. In this form the 
shell is spiral, like an ordinary snail's shell, and each 
coil of the spiral consists of four chambers. The Fora- 
minifera vary considerably in size : some are perfectly 
microscopic, while others have a diameter of about half- 
an-inch. These latter are some of the largest of the 
Animalcules. 
We notice next another type that is equally striking 
— a type to which the term Radiate-animalcule may be 
