MASS TISSUES. 33 
flagellate, amoeboid and gland-cells, though possibly the 
same cells may assume each of these forms. Again, a 
ciliated glandular epithelium is very common, gland-cells 
being interspersed amongst the ciliated cells. 
2. Mass Tissues.—Of tissues in three dimensions, or 
mass-tissues, we may distinguish the most important as— 
(1) Connective tissues, (2) Muscular tissues, and (3) 
Nervous tissues :— 
Fig. 8. (1) Connective tissues——In these 
Connective Tissuzs. the cells themselves usually become 
(x and 3 after Howes). subservient to the substance around 
or within them, which is secreted by 
them— when outside the cells this is 
termed the matvix. We can here 
only notice the most important :— 
(a) Fibrous connective tissue con- 
sists of a matrix in which there are 
intersecting elastic fibres. Certain 
of its cells commonly secrete large 
globules of fat and give rise to 
adipose tissue. 
(6) Chordoid tissue.—These cells 
secrete in their substance a clear 
fluid matrix which almost entirely 
replaces the protoplasm, the nuclei 
being squeezed to one side. The 
whole forms a strong elastic sup- 
porting tissue. It is a modified 
glandular epithelium, and is best 
known in the notochord of Verte- 
brata. 
(c) Cartilage.—In cartilage the 
cells lie scattered in a dense mass 
of secreted matrix, which may be 
clear or hyaline, or may show a 
fibrous structure. 
Cartilage. 
M,. 4 
