34 MASS TISSUES. 
(@) Bone.—The cells 
or bone-corpuscles form 
a meshwork of finely 
branched cells, anasto- 
mosing in every direc- 
tion, and the matrix con- 
sists of concentric layers 
or lamellee of calcareous 
matter, producing a 
hard, dense, supporting * 
tissue. 
Bone, more highly magnified. 
(2) Muscular tissue.—The cells or fibres are aggregated 
into masses, and each is usually elongated in the direction of 
contraction. ' The property of contractility is concentrated 
in them, and they may or may not show a cross striation. 
In the higher types the whole cell is modified into a fibre, 
but in Hydra, Ascaris, and other types, only a part of it is 
so modified. 
Fig. 9.—MUSCULAR TISSUE. 
(After Howes) 
x Transverse section of small muscle. z. Muscle-fibres, 
(3) Vervous tissue.—The primary nervous elements are 
nerve-cells. These are commonly stellate (multipolar), but 
they may have only one or two branches (unipolar or 
bipolar). The branches pass from the cells to muscles, 
or to sensory epithelium, and they form nerve-fibres. A 
number of nerve-fibres aggregated together and enclosed 
in a sheath form a nerve. 
