234 A HISTORY OF RECENT CRUSTACEA 
Latreutes, Stimpson, 1860. Mandibles without cutting 
edge or ‘palp.’ Wrist three-jointed. 
Hippolite, Leach, 1813. Mandible with cutting edge, 
without ‘palp.’ Wrist three-jointed. 
Cryptochéles, Sars, 1869. Mandible with cutting edge, 
without ‘ palp.’ Wrist seven-jointed. 
Bythocadris, Sars, 1869. Mandible with cutting edge, 
without ‘ palp.’ Wrist nine-jointed. 
Spirontocdris, Spence Bate, 1888. Mandible with 
rudimentary cutting edge, and ‘palp. Wrist 
seven-jointed. 
Nauticdris, Spence Bate, 1888. Mandible without 
cutting edge, with three-jointed ‘ palp.’ Wrist 
seven-jointed. 
[ Hetairus |, Spence Bate, 1888. Mandible with cutting 
edge and two-jointed ‘ palp.’ Wrist seven-jointed. 
Merhippoljte, Spence Bate, 1888. Mandible with 
cutting edge and three-jointed ‘palp. Wrist 
many-jointed. 
Chorismus, Spence Bate, 1888. Mandible with rudi- 
mentary cutting edge and three-jointed ‘ palp.’ 
Wrist many-jointed. 
Amphiplectus, Spence Bate, 1888. Mandible with 
cutting edge and two-jointed ‘palp.” Wrist 
many-jointed. 
Of these genera the first is not new but newly named, 
having been originally called Cyclorhynchus by de Haan, 
and then Rhynchocyclus by Stimpson, in allusion to the 
laterally compressed, deep, and terminally orbiculate 
rostrum. Unfortunately both names were preoccupied. 
The new name literally means a broad platform, but was 
evidently given under the impression that, as in English 
the word rostrum may stand either for a beak or a plat- 
form, so the Greek word for a platform might equally well 
stand for a beak, which is not exactly the case. The dis- 
tinctions between this genus and Latreutes reach almost a 
vanishing point, when it is observed that both Stimpson 
and de Haan give to the type species Platybema planirostris 
