STALK-EYED CRUSTACEA 



429 



Family I. Scyllaridae. 

 Family IL Palinuridae. 



Synopsis of the Families. 



A. The external antennae are short, and in the form 

 of flat plates. — {Scyllaridcs.) 



B. The external antennee are long, and in the form 

 of long-, stiff, multiarticulate flagella. — {Pa/iiniridce.) 



Family I, Scyllaridae. 



ScyllaridcE . . . . Spence Bate, Dana. 



Carapace horizontally depressed. Eyes implanted 

 in orbits excavated in the dorsal surface of the carapace 

 The external antennae short, in the form of flat plates. 

 The mandibles have an unarticulate palp. The legs of 

 the posterior pair of the female are minutely chelate. 



Synopsis of the Genera. 



A. The carapace is wider than long; the 

 orbits are situated at some little distance from 

 its anterior angles. — (Idaccus.) 



B. The carapace is longer than wide ; the 

 orbits are situated at a short distance from its 

 anterior angles. 



a. The external antennae are close. The 

 gills are twenty-one in number. There is 



\^^ — -* 



Ibaccits. 





Arcius. 



an external appendage to the external maxillipede. — 



{Scj'llanis.) 



