PLATE VII. 



Common Craypish (Astacus Fluviatilis), 

 Male, 



Dissected so as to show its nervous, digestive, circulatory, and reproductive systems 

 in situ; the various organs having been exposed in an antero-posterior vertical view, 

 by the removal of the teguinentary skeleton, the muscles, and the hepatic lobes of 

 the left side. 



a. Oesophagus leading vertically upwards from the mouth into 



the stomach. The labrum, the free edges of the mandibles, 

 and of the two maxillae, are faintly indicated on the right 

 side of the mouth anteriorly to the three foot-jaws. 



b. Cardiac portion of stomach. Superiorly and anteriorly the 



stomach is still retained in its natural position a long way 

 anteriorly to the line of the entrance of the oesophagus, 

 the anterior gastric muscles which took origin superiorly to 

 the supra-oesophageal ganglia, o, from the under surface of 

 the ventral wall of the Hollow rostrum, and attached them- 

 selves to the cardiac plate, having been left intact ; whilst 

 the anterior wall of the stomach has been displaced a little 

 backwards in order to give a better view of the stomato- 

 gastric nerves. 



c. Lateral valvular prominence of pyloric portion of stomach. 



d. Hepatic lobes of right side where they came into apposition 



with those of the left side which have been now removed 

 along the infero-median line. 



e. Orifice by which the hepatic lobes of the left side opened into 



the digestive tract immediately posteriorly to the pylorus, 

 and below the coecal process, n. 

 f Intestine passing with the straight course characteristic of 

 Crustacea, with the exception of Lynceus, to the anus. 



