FORA MINIFERS. 
555 
times the length of the body. Every 'fibre exhibits an up and down stream of 
granules suspended in clear hyaline sarcode. A diatom, infusorian, or other edible 
prey, coming in contact with the pseudopods, is covered with a mass of protoplasm 
formed by fusion of several filaments, drawn down to the mouth of the shell and 
engulfed. Gromia moves by means of its pseudopods, which fix themselves and 
draw the body along. When alarmed, the animal withdraws into its membranous 
test. 
The sandy Foraminifera, which are mostly deep-sea types, are composed of 
masses of sarcode, sometimes of considerable size, which form shells or cases of 
agglutinated mud, sand-particles, or sponge-spicules. They frequently attain a 
a Hyperammma ramosct ; b and c, Astrorhiza limicolcc ; b, Entire ; c, Cut open. 
large size; for instance, Batkysiphon, from the Atlantic and also from fourteen 
hundred and twenty-five fathoms off Amboyna, forms a slender annul ated tube, two 
inches in length, and open at each end, the Avails of the tube being composed of 
cemented sponge-spicules. Haliphysema is found in shallow water in the North 
Atlantic in the form of minute club-shaped bodies, one-twentietli of an inch in 
height, with the narrowed lower end attached by a disc to zoophytes, etc., and with 
the surface bristling with sponge-spicules. Hyperammina, generally distributed in 
from sixty to three thousand fathoms, makes a test of cemented sand-grains and 
sponge-spicules, at first forming a globular chamber with a long branched neck, the 
branches of which again branch. Astrorhiza forms stellate single-chambered shells 
of fine mud, slightly cemented, and lined inside by a smooth membrane; at the 
ends of the arms are large openings for the pseudopods; the diameter of the disc 
is about one-fifth of an inch, and that of the entire shell about half an inch; the 
animal lives in comparatively shallow water (about twenty fathoms), in the North 
Atlantic. Certain other sandy species are characterised by the regular form of 
their shells, which resemble those of calcareous species. The imperforate cal¬ 
careous species are usually milk-white. The shell possesses only one or a few 
