STRUCTURE AND PHYSIOLOGY OF ANIMALS 



27 



A series of tissues in which the cells are, in most instances, sub- 

 ordinate, as regards bulk, to substances formed between them, is 

 the group known as the 



connective tissues, in- T^F"F7 r*-f- .*, 



eluding gelatinous connec- 

 tive tissue, retiform con- J\ 

 nective tissue, fibrous ^ 

 connective tissue, cartilage, 

 and bone. In the majority 

 of forms of connective 



tissue the cells lie em- *f ^ 



bedded in an intermediate 

 substance called the matrix 

 or ground-substance of the 

 connective tissue. 



In the case of gelatinous ? \ 



connective tissue (Fig. 13) 

 the ground-substance (g) 

 is of a gelatinous char- 

 acter, sometimes supported 

 by systems of fibres (ef), 

 and the cells are usually 

 stellate or starshaped with radiating processes. Retiform or 

 reticulate connective tissue (Fig. 14) consists of stellate or branch- 

 ing cells with processes which are prolonged into fibres the 



v - 



tf 



FIG. 13. Gelatinous . connective' tissue of a Jelly- 

 fish, bi, epithelial cell passing (into the jelly; 62. 

 branched cells in the jelly ; e, epithelium ; g, gela- 

 tinous matrix ; ef, elastic fibres. (From Lang's 

 Comparative Anatomy.) 



fibres from neighbouring 

 cells joining so as to form 

 a network. In this form of 

 connective tissue there is 

 no true ground-substance 

 the inter-spaces between 

 the cells being filled with 

 other tissue elements. 



Fibrous connective tissue, 

 which is a very common 

 form, has a ground-sub- 

 stance containing gelatin, 

 consisting mainly of 

 numerous fibres, usually 

 arranged in bundles. 

 Thicker yellow elastic fibres 

 may be present among the 

 others, and may be so 

 numerous as to give the 

 entire tissue an elastic 



character. Associated with fibrous tissue, and produced by modi- 

 fication of its cells, is adipose m fatty tissue (Fig. 15), which consists 



FIG. 



14. Regular connective 

 Lang.) 



tissue. (From 



