55h PHILOSOPHY OP ZOOLOGY. 



*** Superior antennae with a moderate peduncle. 

 ST. EcRYDicE. 28. LiMNORiA. 29- Cymothoa. 

 c. Tail terminated zaith tivo seta. 



30. Apseudes. 



D. Tall furnished with styles. 

 Division I. Interior antennae distinct. 

 Subdivision 1. Styles of the tail exserted. Anterior 

 legs monodactyle. 



31. Jamiea. 32. AsELLUs. 



Subdivision 2. Styles of the tail not exserted. Ante- 

 rior legs simple. 



33. I^iiA. 



Division II. Interior antennee not distinct. 



Subdivision I. Styles of the tail double, with a double 

 footstalk. 



34). LiGiA, 



Subdivision 2. Styles of the tail four, the latter ones 

 biarticulate. 



* Body not capable of contracting into a ball. 



a. External antennae eight jointed. 

 35. Philoscia. 36. Oniscus. 



b. External antenna with seven joints. 



37. PORCELLIO. 



** Body contractile into a ball. 

 3S. Armadillo * 



Section %^—Entomostraca. 



Branchiae irregularly placed with respect to the legs, and 

 never concealed under the margin of the shield. 



* The last five genera being ten-estrial, and consequently having pulmo- 

 nary aerating organs, ought not to be inserted among the Crustacea. They 

 should probably form a group by themselves, in connection with the Myria- 

 poda. 



