364 



TRANSACTIONS LIVERPOOL BIOLOGICAL SOClKT\ 



fourth sternal muscle chamber, and arises from the fourth 

 thoracic sternum. Its course is outward, upward and 

 backward, and at its outer extremity it is inserted on a 

 broad tendon lying on the ventral side of the basi-ischium, 

 mid-way between the two hinges (fig. 21, a.f.B., Text 

 fig. 10, *.). 



Fig. 10. — The proximal end of the chela, after all the soft tissues have 

 been removed. The tendons of the muscles moving the coxa and 

 basi-ischium are shown. (The upper side of the figure is dorsal, 

 and the right side is the anterior end.) 



Coxopodite. — a. = dorsal hinge ; 6. = ventral hinge ; c. = tendon of 

 flexor muscle ; d. = tendon of extensor muscle. 



Basi-ischium. — e. = posterior extensor muscle ; /. = anterior extensor 

 muscle ; g. = lesser posterior flexor muscle ; h. = greater posterior 

 flexor muscle ; lc. — anterior flexor muscle ; I. = posterior hinge ; 

 m. = anterior hinge. 



The greater posterior flexor lies in the outer and 

 anterior portion of the fourth pleural muscle chamber, 



