DESCRIPTIVE CATALOGUE 



OF THE 



PHYSIOLOGICAL SERIES 



STRUCTURES CONCERNED IN THE PRE- 

 SERVATION OF THE INDIVIDUAL OR 

 TO ITS ADVANTAGE, 



A, 



ENDOSKELETON. 



(Including all structures that function as an Endoskeleton, 

 whether derived from Ectoderm, Mesoderm, or Endoderm, 

 or the equivalent embryonic layers.) 



A structure specialized to give to the organism support, 

 strength, rigidity, and protection to more deeply seated parts ; 

 in some cases it furnishes the levers and fulcra for the move- 

 ments of parts of the body or advantageous attachment for 

 muscle. Its physical properties are independent of life. 



PLANTS. 



The bundles of thick-walled elongated cells commonly asso- 

 ciated with the vascular bundles act as an endoskeleton. 



The cell-walls of the whole or greater part of a plant may be 

 hardened by lime (especially when exposed to violent waves, 

 e. g. certain Algse = Corallines) or silex (as in grasses and 

 horse-tails), so as to give the necessary strength and rigidity, 

 These cannot be regarded as specialized endo skeletons* 



B 



