76 



GENERAL PRINCIPLES OF ZOOLOGY 



fibres. The fibres may either cross in all directions, or may run essen- 

 tially parallel and in a definite direction. Between them are found the 

 rounded, spindle-shaped or branched connective-tissue corpuscles (fig. 

 41). It is characteristic of vertebrates that the fibres are grouped into 

 bundles, each bundle generally surrounded by connective-tissue corpuscles, 





FIG. 41. Fibrous connective tissue 

 of an Actinian. 



;? 



FIG. 42. Areolar fibrous connective 

 tissue (after Gegenbaur). 



metamorphosed into flat cells. The bundles, loosely interwoven, run in 

 all directions (areolar connective tissue, fig. 42), or they may be parallel, 

 forming a compact mass of fibres (tendinous tissue fig. 43). The fibrils 

 of the fibrous connective tissue cf the vertebrates have the peculiarity 

 not met with elsewhere, they are composed of glut-in, and upon boiling 

 become gelatine or glue. 



FIG. 43. Tendinous tissue (after 

 Gegenbaur). 



i 









FIG. 44. Cartilage (after Gegen- 

 baur). r, perichondrium; b, transition 

 into typical cartilage (a). 



Elastic Tissue. In all fibroas connective tissue there may appear, 

 as a further constituent, elastic fibres; they may indeed supplant the ordi- 

 nary connective-tissue fibrils and become the predominant element of the 

 tissue, which is then called elastic tissue. 



