HOMARUS AMERICANUS MILNE-EDWARDS 143 



from the liver to the abdomen and lying on the endosternites 

 one sees in the depth the powerful right flexor abdominis. In 

 the abdomen one can see under the posterior aorta the dark 

 intestine clearly separated from the last section of the alimentary 

 canal, the rectum. If the specimen is a male, a tube will be seen 

 running from behind the heart to the base of the fifth leg this 

 is the left vas deferens; and the testis will be found lying along- 

 side the intestine and partly imbedded in the liver. If the speci- 

 men is a female, the ovary occupies, when fully developed, all 

 the space from the stomach to the fourth or fifth abdominal 

 segment. 



23. Remove the right wall of the cephalic portion, cut the 

 alimentary canal between oesophagus and stomach, cut the ceph- 

 alothorax transversely close behind the adductors of the man- 

 dibles, remove all organs except the green glands and nervous 

 system and make a drawing showing the rear view of the cut 

 surface. Above the oesophagus you will notice the large brain or 

 supracesophageal mass and running on each side of the oesophagus 

 from the brain to the subcesophageal mass a long connective. 

 Between the muscle of the second antenna and this connective 

 appears one of the large green glands. 



24. Open the "hand" of the big claw by removing the entire 

 outer wall. Make a natural-size drawing showing the outline of 

 the claw, the point of articulation between the movable finger 

 and the hand, the large and heavy flexor and the considerably 

 smaller extensor. 



25. Boil the stomach in a 10% solution of potassium hydrate, 

 wash it in water and examine first from above, then from the 

 side. The dorsal pouch leading into the dorsal tooth marks the 

 position of the gastric mill. The soft sac in front of the gastric 

 mill is the cardiac sac, the one behind the gastric mill the pyloric 

 sac. The hard transverse ossicle in front of the pouch is the 

 cardiac ossicle. The hard ossicle forming, as it were, a roof 

 over the pouch is the pyloric ossicle. The floor of the pouch is 

 formed by the urocardiac ossicle. The latter is articulated with 



