STALK-EYED CRUSTACEA. 



Class CRUSTACEA. 



Animals having the body composed of segments, in 

 general very distinct, motile, and of considerable hardness, 

 without an internal skeleton properly so called, and carry- 

 ing a double series of appendages, almost always very 

 distinctly articulated, consisting of antennae, jaws, etc., 

 and of limbs of which the number is usually five or seven 

 or eight pairs ; the nervous system is in general very 

 distinct, being composed of ganglionic centres and con- 

 necting cords; the respiration, in general aquatic, carried 

 on by means of gills or membranes ; the circulation, in 

 general very distinct, is almost always through a special 

 heart and blood-vessels ; the sexes are distinct. 



Subclass Podophthalmata. 



PodophtJiahnata . . Miers. 

 Podop]it]ialmia . 



Podophihalmiens 

 PodophtJiahna . 

 Crustaces pcdiodes 



Dana. 



H. Milne Edwards. 



Leach, Linne. 



Lamarck. 



Mouth armed with mandibles and jaws for mastica- 

 tion ; in general gills properly so called ; eyes on stalks, 

 and movable ; rod-like thoracic limbs ; a carapace. 

 I 



