THE PLANARIAN 



97 



the animals have been living. Record by drawings the changes ob- 

 served at daily intervals for one week. Understand the cellular 

 changes that occur. 



p^ar^/7x 



^ SvQT'i/ phopym^hcath \ \ genital pore' ^nerve cord 

 nerve, cord mouth ductus de/erem ^oviduci 



- oi/arz/ 



' ductus- 

 efferent 



ductus 

 deferens 



mouth -~_ 



genital 

 pone. -. ^ 



z^o/^^/ands -J 



- -pharynx 





Fig. 47.— Structure of a planarian. Above, diagram of a planarian in lateral 

 view. Below, diagram of the reproductive system of a planarian. 



(f) The reproductive organs are seasonal in occurrence and cannot 

 be studied in living planarians. If they are to be studied stained 

 material will be furnished and further directions will be given. The 

 animals are hermaphroditic. Fertilization is internal, following sexual 



