Fig. 117. — Hirudo medicinalis. A, dorsal; B, ventral aspect, a, anus; <z. s, 

 anterior sucker; e. /, first pair of eyes; e. 5, fifth pair; gp. H" , male gonopore; 

 gp. £, female gonopore; mth, mouth; np.i, first pair of nephridiopores; 

 11 p. ly, seventeenth pair; p. s, posterior sucker; s.p, sensory papillae; I-XXVI, 

 segments. (Partly after Whitman-) 



204 



