ZOOLOGY FOR MEDICAL STUDENTS 



CHAP. 



The basal segment of each is enlarged to form a stout blade with stiff 

 spikes or bristles projecting from it. This blade-like development is 

 known as a gnathobasBj and the development of a gnathobase is one of 



c.e. 



A King-crab {Limulus), female, 

 soma ; p, prosoma ; (, telson. 



Fig. 98. 

 A, dorsal view. c.e, Central eye ; l.e, lateral eye ; 0, opistho- 



the most characteristic of the modifications of the arthropod limb for 

 purposes of mastication. The seventh appendages (Fig. 98, B, VII) are a 

 pair of stout rod-like organs called chilaria, just behind the mouth. The 

 eighth appendages (VIII) are flattened plates, continuous with one 



