PLATE XIV. 



Class HIBUDINEA. 

 THE MEDICINAL LEECH (Hirudo mcdicinalis). 



FIG. 1. DISSECTION FROM THE VENTRAL ASPECT, x 1. 



m. mouth : p. penis protruded : v. external opening of the vagina : 

 s. 1 -^ 17 segmental organs: c. 1 -^ 11 caeca or diverticula of the 

 stomach: s. v. seminal vesicle : o. ovary : .M. 9 testes : v.d. 

 vas deferens : v. e. vas effereus : i. intestine : g. nerve ganglion 

 on the ventral cord : p. s, posterior sucker. 



FIG. 2. DISSECTION FROM THE LEFT SIDE, x 1. 



m. mouth : g. supra-oasophageal nerve ganglia, or brain : r. circum- 

 resophageal nerve ring : v. ventral nerve cord with ganglia : 

 s.^-s. 17 segmental organs : c. 1 -^ 11 cseca or diverticula of the 

 stomach : i. intestine : a. anus. 



FIG. 3. HEAD EEGION : VENTRAL ASPECT : SHOWING THE JAWS, x 3. 

 FIG. 4. ONE OF THE JAWS REMOVED, x 15. 



FIG. 5. TRANSVERSE SECTION THROUGH THE BODY, x 6. 



m. muscular layers : d. dorsal vessel : I. lateral vessel : s.s. vesicle of 

 the segmental organ : t. testis : v. ventral vessel enclosing the 

 nerve cord : s. stomach. 



FIG. 6. HEAD EEGION : DORSAL ASPECT : SHOWING THE POSITION OF THE EYES. 

 x 3. 



