NEREIS VIRENS SARS 103 



2. Make a drawing showing the side view on the same scale. 

 Label all parts, including mouth. 



3. Make a drawing of the ventral surface of the posterior ten 

 segments. Label anus, anal cirri, parapodia and nephridio- 

 pores. 



4. Place a specimen with a protruded proboscis in the same 

 tray and make a drawing as in No. i. Label proboscis, pharyn- 

 geal denticles and jaws. 



5. With the aid of a forceps tear out a parapodium from one 

 of the middle segments of the worm. Place it in a Syracuse dish 

 with glycerine under the dissecting microscope and make a 

 quarter page drawing of it. Label the notopodium and neuro- 

 podium. In the former label the upper ligula with the dorsal 

 cirrus, chetae, aciculum and lower ligula. In the neuropodium 

 label upper ligula, chetae, aciculum and lower ligula with the 

 ventral cirrus. 



6. Tear out a parapodium from the first segment behind the 

 head, examine in the same manner and make a drawing. Label 

 parts. 



7. With the aid of two needles tear the parapodium to free 

 the chetae. Place a cheta on a slide in a drop of water under 

 a cover glass, examine under microscope and make a drawing 

 showing the shaft and blade. 



8. Open the worm along its back in a line parallel to the mid- 

 dorsal line from head to anus and fasten the body wall with pins. 

 Remove ventral longitudinal muscles bit by bit. Make a draw- 

 ing of the anterior third showing dorsal longitudinal muscles, 

 septa, digestive organs, circulatory organs, nephridia and su- 

 pracesophageal ganglion. Label septa, pharnyx, oesophagus, 

 intestine, digestive glands, protractors and retractors of the 

 proboscis, dorsal vessel (on body wall), transverse vessels, 



dorsal peristomial cirri; n 1 , ganglion; n, nerves for the dissepimenta; m, 

 parapodial nerves; i, parapodial branch; h, ventral chain of ganglia; C, 

 cerebral ganglion; o, nerve passing through dissepiment to preceding seg- 

 ment; k, parapodial ganglion. 



