504 



TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. 



A considerable degree of specialisation is shown by 

 the limbs. Some are used for facilitating rapid egress 

 and retreat into the shell, some for locomotory purposes, 

 the telson and uropods for hanging on passively to the 

 shell, and the pleopods for causing a flow of water in the 

 shell, and (in the female) for carrying the developing 

 eggs. 



The male and female differ only in the disposition 



and number of the pleopods. 



The appendages 



arranged as follows: — 







Cephalon. Somite I. 



1st Antennae. 





II. 



2nd 





III. 



Mandibles. 





IV. 



1st Maxillae. 





V. 



2nd Maxillae. 



Thorax. Somite VI. 



1st Maxillipedes. 





VII. 



2nd 





VIII. 



3rd 





IX. 



1st Pereiopods. 





X. 



2nd 





XI. 



3rd 





XII. 



4th 





XIII. 



5th 



Abdomen. 









Female. 





Right 



). Left. 



Somite XIV. 



Absent. Absent. 



XV. 



,, 



1st Pleopod. 



XVI. 



,, 



2nd ,, 



XVII. 



,, 



3rd ,, 



XVIII. 



5 3 



4th ,, 



XIX. 



Uropod. TJropod. 



