— 4i — 



of the wings of the heart, and the structui^ of the cephalic 

 end of the aorta. Usually it is very difficult to determine 

 the number and arrangement of the chambers of the heart 

 in Corydalis ; this point may be omitted, therefore, in this 

 elementary course. Sometimes, however, some of the 

 valves can be easily seen. They occur near the middle of 

 each abdominal segment just opposite the point where the 

 cephalic edges of the larger wing-muscles join the heart. 



Review. — Take a specimen that has been slit on the 

 dorsal surface and make a preparation similar to the one just 

 studied except that it is opened along the dorsimeson. Re- 

 view the work on internal anatomy indicated above except- 

 ing those parts referring to the nervous system, which will 

 be concealed by the alimentary canal in this specimen, and 

 to the circulatory system, which will be destroyed in the 

 preparation of the specimen. 



Note especially the form of the reproductive organs, and 

 determine if the specimen is of the same sex as the one pre- 

 viously studied. If it is not, complete the work on the re- 

 productive organs indicated above ; if it is of the same sex 

 other specimens should be examined after the work on this 

 one is completed. 



The Suspensory Nerves of the Alimentary Canal. — 

 Gently push the intestine to one side and note the two fine 

 threads extending caudad from the small intestine. Trace 

 out the connection of these threads or nerves with the 

 nervous system. Note the fine branches of these nerves 

 that extend to the caudal part of the intestine. 



Make a diagram representing a side view of that part of 

 the alimentary canal caudad of the proventriculus, the last 

 three gangalia of the nervous system, and the nerves just 

 described. 



The Peritoneum. — Cut the alimentary canal in two be- 

 tween the ventriculus and the first bend in the intestine. 

 Remove that part of the alimentary canal caudad of this 



