104 MORPHOLOGY OF INVERTEBRATE TYPES 



ventral vessel, nervous system visible beneath it, and suprace- 

 sophageal ganglion. 



9. Remove alimentary canal and ventral blood-vessel and 

 make a drawing showing nervous system and nephridia. 



10. Place the prepared isolated segment of the worm in a 

 Syracuse dish with water under dissecting microscope and make 

 a half page drawing showing parapodia, dorsal longitudinal 

 muscles, ventral longitudinal muscles, oblique muscles, dorsal 

 vessel, intestine, ventral vessel, nervous system and nephridia. 



11. Examine under microscope a prepared slide with a cross- 

 section through Nereis virens. Make a half page drawing of it 

 and label all parts mentioned in No. 10 and also cuticle, cir- 

 cular muscles, dorsal mesentery of the intestine, gonads, parietal 

 and visceral layers of the peritoneum. 



