96 MORPHOLOGY OF INVERTEBRATE TYPES 



middle of the pharynx, lifting with a forceps and cutting with 

 scissors the aortic loops and parietal vessels. The removal of the 

 alimentary canal will expose all reproductive organs, nervous 

 system, neural blood-vessels and nephridia. Make a full page 

 drawing showing all structures inclosed in segments seven to 

 seventeen. Label first seminal vesicle with first and second pair 

 of spermothecae, second seminal vesicle with third pair of spermo- 

 thecae, the two vasa deferentia; the first pair of receptacula 

 seminis in the ninth segment, and the second pair of receptacula 

 in the tenth segment if not completely hidden by the spermo- 

 thecae; the pair of small ovaries in the thirteenth segment, the 

 oviducts; and finally the setigerous glands in the eighth to 

 thirteenth segments. 



4. Remove a complete nephridium, place it on a slide in 

 glycerine and examine under low power. Make a drawing show- 

 ing nephrostome, transparent portion, glandular portion and 

 terminal portion. 



5. Remove reproductive organs and lift carefully the nervous 

 system cutting the side nerves. Place the nervous system on a 

 slide and examine under low power. Make a drawing showing 

 supracesophageal ganglion and at least five ventral ganglia. 



6. Examine under low power the prepared section through 

 the region of the aortic loops. Make a drawing showing cuticle, 

 hypodermis, circular muscles, longitudinal muscles, dorsal 

 vessel, ventral vessel, nervous system, oesophagus and such 

 other organs as may be seen. 



7. Examine under low power the prepared section through the 

 region of the twentieth to thirtieth segments. Make a drawing 

 showing a, b, c, and d bristles, cuticle, hypodermis, circular 

 muscles, longitudinal muscles, intestine with typhlosole and 

 chloragogue cells, dorsal vessel, ventral vessel, nervous system, 

 median and lateral subneural vessels and nephridia. 



8. Examine under high power (400 diameters) the prepared 

 section through the clitellum and make a drawing showing the 

 hypodermis with gland cells. 



