76 



GENERAL PRIXCirLES OF ZOOLOGY 



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

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

 rounded, spindle-shaped or l.iranched connective-tissue corpuscles (hg. 

 It is characteristic of vertebrates that the fibres are grouped into 



41 



bundles, each bundle L^^enerally surrounded by connective-tissue corpuscles, 





'Ml 



Fig. 41. — Fibrous connective tissue 

 of an Actinian. 



Fig. 42. — .\rcolar fitirous connective 

 tissue (.after Llegenbaur). 



metamorphosed into fiat cells. The bundles, looselv interwoven, run in 

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

 forming a compact mass of fibres [tcndi)ious tissue fig. 43). The librils 

 of the librous connective tissue of the vertebrates have the peculiarity 

 not met with elsewhere, they are composed of glulin, and upon boiling 

 become gelatine or slue. 



^^^''^['^^ij^-^.^^^^'^.^r 



;v fSv^._CJ^.^^^J^J:^ 



1^1- 





A*f 



Jj£ 



Fig. 43. — Tendinous tissue (after 

 Gegenbaur). 



Fig. 44. — Cartilage (after Cegen- 

 baur). r, ]iericliimclriun^, />, transilion 

 into typical cartilage (a). 



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

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

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

 tissue, which is then called elastic tissue. 



