STALK-EYED CRUSTACEA 5 



the sternum or in the basal joint of the last pair of legs, 

 thence passing through a channel in the sternum beneath 

 the abdomen. Gills, usually fewer than nine, occupy but 

 a small space in the branchial chamber. 



C. Space in front of the mouth very short, but 

 broad. 



c. Carapace broad in front, often subquadrate, some- 

 times subglobose, transverse or arcuate ; never rostrate 

 in front. — {Catonietopa.) 



III. The canal from the branchial cavity passes out 

 at the middle of the palate, which is produced forwards. 

 The buccal cavity is narrowed and produced in front, 

 triangular. The male genital appendages are inserted 

 in the basal joint of the fifth pair of legs. The gills are 

 seven to nine in number. 



D. Space in front of the mouth very small. 



d. Carapace is transverse ; arcuate anteriorly, or 

 subglobose. — {Oxystoniata.) 



Tribe I. Oxyrhyncha. 



OxyrhyncJia Miers. 



OxyrJiyncJii (part) . . . Latreille. 



Oxyrliinques H. Milne Edwards. 



Maioidea vel OxyrJiyncJia . Dana. 



Carapace more or less narrowed in front, and usually 

 rostrated, with the branchial regions well developed. 

 Hepatic regions small. Epistome usually large. Buccal 

 cavity quadrate, with the anterior margin straight. Gills 

 nine in number ; their efferent channels terminating at 

 the sides of the palate. Internal antenna; longi- 

 tudinally plicated. The fifth articulation of the external 



