STALK-EYED CRUSTACEA 205 



(exognath) never reaches beyond the half of the fourth 

 joint, and is often very small. 



The palatal ridges reach quite to the anterior margin 

 of the buccal cavit}', and form two lateral well - marked 

 channels. The terminal joint of the walking legs is 

 armed with spines. The colour of the carapace is usually 

 some shade of brown. 



Synopsis of the Genera. 



I. The posterior margin of the fourth joint of the 

 external maxillipedes equals the anterior margin of the 

 third joint, against which it is applied. 



A . The external appendage of the external 

 maxillipedes is not as long as the third joint ;' n 

 efferent branchial channel without teeth or 



Soine Pscndofhclphitsa. 



a. Superior margin of front less advanced than inferior 

 margin, or about equally advanced with it ; antero-lateral 

 teeth small, often tuberculiform. — {^P scudotlielplnisa^ 



b. Superior margin of front projecting over the surface 

 of the front, which retreats and is not visible on a dorsal 

 view ; antero-lateral teeth large and spiniform. — (^Potaino- 

 cai'cinus.) 



B. External appendage of the external 

 maxillipedes longer than the third joint ; 

 efferent branchial channel with a tooth or 

 spine projecting from the upper side near 

 the anterior end. — {Epiloboccra}) po wi- 

 ll. Posterior margin of fourth joint of external maxilli- 

 pedes one-half the width of the anterior margin of the 

 third, and articulated with the outer half of the latter. — 

 {Rathbunia.) 



