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 — 

 (i) Connective tissues, (2) Muscular tissues, and (3) 

 Nervous tissues : — 



Fig. 8. 

 Connective Tissues. 



(i and 3 after Howes). 



Fibrous Tissue. 



Chordoid Tissue. 



& 



Cartilage. 



M. 



(i) Connective tissues. — In these 

 the cells themselves usually become 

 subservient to the substance around 

 or within them, which is secreted by 

 them— when outside the cells this is 

 termed the matrix. 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. 



(b) 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. 



4 



