252 MORPHOLOGY OF INVERTEBRATE TYPES 



Make a full page drawing of all organs as exposed to view. 



11. Remove the posterior venae cavae and the urinary gland 

 together with the nephridial arms of the anterior vena cava 

 passing through them, thus exposing the systemic heart. Cut the 

 sheet of integument which fastens the right gill (on your left) 

 to the mantle and turn the gill so as to bring into view the 

 branchial artery which runs from the branchial heart along the 

 gill. Make a drawing showing the branchial hearts, the left 

 branchial vein, the right branchial artery, the systemic heart, 

 the base of the anterior aorta and the posterior aorta with the 

 three mantle arteries. 



12. Remove the arterial system, branchial hearts and gills. 

 Carefully push to the left the digestive organs, thus exposing 

 to view the male reproductive organs. Make a drawing showing 

 the testis with its mesentery or tendon attached to the wall of a 

 capsule of the ccelome, vas defer ens, the convoluted vesicula 

 seminalis, the thin spermatophoric duct with the prostata and 

 appendix connected with it at its beginning, the large sperma- 

 tophoric sac filled with spermatophores, and the penis. 



13. Open the spermatophoric sac and remove some of the 

 spermatophores into a shallow dish with water. Examine under 

 low power (microscope) showing the double walls with the 

 ejaculatory apparatus at the rear end. In the latter show the 

 flask-shaped sac and the filament with the spring. 



14. With a razor cut into the head in the median line between 

 the eyes both above and below the buccal bulb without injuring 

 the latter. Carefully remove the entire alimentary canal with 

 its glands allowing it to float in water on one side. Make a 

 drawing showing the buccal bulb with the upper and lower jaw, 

 the anterior aorta and the oesophagus with the liver through which 

 they pass, the stomach, characterized by its thick muscular walls, 

 the thin and large stomach pouch, the short intestine passing 

 between the two lobes of the pancreas and the rectum with the 

 rectal papilla. Show also the two hepatic ducts connecting the 

 liver with the pancreas and, if possible, the hcpato-pancreatic 



