PLATE XIII. 



LOBSTER AND CRAYFISH continued. 



GENERAL ARRANGEMENT OF INTERNAL ORGANS 



FIGS. 1, 2, 3. BODY IN SECTIONAL PLAN AND ELEVATION 



/ Mouth. 

 I Gullet. 



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

 ALIMENTARY SYSTEM ! pyloric or posterior eud (Gr. puloros, a gatekeeper) leading into 



I Intestine ending in 

 I Anus. 

 \ Liver made up of two symmetrical halves. 



f*T"pf TTT ATOK.Y ^>YSTFM s 



I Arteries Sternal, superior abdominal, and inferior abdominal. 



KESPIRATORY SYSTEM Branchioe (Gr. gills), twenty on each side in Lobster, eighteen ill Crayfish. 

 HENAL SYSTEM Green glands situated at the base of antennas. 



( Supra-cesophageal ganglia. 



, T i Circum-cesophageal commissures. 



NERVOUS SYSTEM . < 



1 Sub-cesophageal ganglia. 



V. Chain of eleven ganglia. 



( Testt's with their vasa deferentia opening on the base of last thoracic 



T, appendages (llg. 2). 



REPRODUCTIVE SYSTEM 



J Ovaries with their oviducts opening on the base ot last thoracic appcn- 



V clages but two (fig. 3). 



