25 



PLATE XIII. 



LOBSTER AND CRAYFISH 



GENERAL ARRANGEMENT OF INTERNAL GROANS 



Fius. 1, 2, 3. HODY IN SECTIONAL PLAN AND ELEVATION 



/ Mouth. 

 I Gullet. 



I Stomach, with its cardiac or anterior end (Or. kardia, the heart), and its 

 ALIMENTARY SYSTEM ( pyloric or posterior end ((Jr. puloros, a gatekeeper) leading into 



I Intestine ending in 

 I Anus. 

 \ Liver made up of two symmetrical halves. 



CIRCULATORY SYSTEM 



( Arteries eternal, superior abdominal, and inferior abdominal. 



RKSPIRATORY SYSTEM Branchiae (Gr. gills), twenty on each side in Lobster, eighteen in Crayfish. 

 UENAL SYSTEM Green glands situated at the base of antenna;. 



( Supra-cesophageal ganglia. 

 NERVOUS SYSTEM , J Circum-oesophageal commissures. 



I bub-ccsophageal ganglia. 



V Chain of eleven ganglia. 



f Testes with their vasa deferentia opening on the base of last thoracic 



REPRODUCTIVE SYSTEM appendages (fig. 2). 



i Ovaries with their oviducts opening on the base of lust thoracic appcn- 

 V dages but two (lig. 3). 



4 



