The. Lobster. 85 



The liver is the voluminous organ, of light green color, 

 that fills up the greater part of the thorax. Note the seg- 

 mental arrangement of the thoracic and abdominal muscles. 

 Carefully remove the tissues at the base of the second 

 antennae, exposing the green glands. 



Draw the animal as seen from above, usir\g only the 

 lightest outlines, as the details are to be put in after further 

 study. 



Remove the muscular and skeletogenous tissue from the 

 lateral third of the left side of the body, thus giving a new 

 view of the viscera. Lay the animal in water and note the 

 boundaries of the organs already studied. 



Probe through the mouth into the stomach. What direc- 

 tion does the short (esophagus take ? The larger, more chiti- 

 nous, anterior or cardiac portion of the stomach is separated 

 from the posterior or p\loric portion by a groove running 

 diagonally from the dorsal to the ventral line. Do you find 

 that the insertion of muscles is in any way related to the 

 hardened areas of the stomachic walls? Are there any 

 pouch-like out-pushings of the pyloric portion? Is the 

 pyloric portion chitinous ? The whole organ resembles the 

 exoskeleton and is, indeed, formed from an in-pushing of 

 the outer covering of the body. 



Pass to the posterior end of the alimentary tract and note 

 that the rectum, the section lying behind the middle of the 

 penultimate segment, is somewhat different from the straight 

 mesenteron or intestine, which connects it with the pyloric 

 portion of the stomach. Inject water through the anus and 

 distend the intestine. Do you find a dorsally projecting 

 sac, the ccecum, arising from the hinder end of the mesen- 

 teron? 



Find the duct which leads from the left lobe of the 



