STALK-EYED CRUSTACEA 311 



A. Three spines on posterior border of carapace, 

 ringers open in a vertical plane. 



a. Three spines conical. — (///a.) 



b. Central spine conical ; lateral spines flattened, 

 triangular. — {Iliacautlia.) 



B. Five spines on posterior border of carapace. 

 Fingers open in a horizontal plane. — {Myropsis.) 



II. The carapace is not produced so as to cover in 

 great part the walking legs. The first pair of legs robust ; 

 the palm and fingers compressed, not long and slender. — 

 (Sect. II.) 



C. External appendages of external maxillipedes 

 broad, with external margin curved. — [Ebalia?) 



D. External appendages of external maxillipedes 

 narrow, with external margin straight. — {Perscphona) 



Section I. 

 mines .... Stimpson. 

 The carapace is not produced over the bases of the 

 walking legs. The palm of the first pair of legs very 

 slender and elongated ; the fingers very slender and nearly 

 straight, or with the tips slightly incurved. The ptery- 

 gostomian channels have usually two notches at the 

 distal extremity. 



I. Ilia. 



Ilia .... Leach, Milne Edwards, Desmarest, 



Latreille, Roux. 

 Leucosia . . Fabricius. 

 Cancer- . . . Linne, Herbst. 



The carapace is globular, and rather swollen than 

 contracted about the hepatic regions ; the anterior pro- 



