91 
PALAZMON. 
Patzmon, Fabr., Bosc., Latr., Leach. 
Astracus, Pennant. 
Cancer, Linné, Gmelin. 
CHARACTER GENERICUS. , 
Antenne interiores pedunculo mediocri, setis tribus articu- 
Jatis terminate ; exteriores infra interiores insertz squa- 
ma magna ad basin, ad apicem unidentata, pedunculo 
adnexa. 
Abdomen articuld secundé anticé et posticé producté ; cauda 
Jamellis duabus foliaceis utrinque instructa, cum inter- 
media pinnam flabelliformem, natatoriam efformantibus. 
Pedes decem ; paria duo antica didactyla, pari antico mi- 
nore ; paria tria postica simplicia, unguibus simplicibus 
instructa. 
Pedipalpi gemini externi caulis interni articulo ultimo acu- 
minato, penultimo breviore. 
PRAWN. 
GENERIC CHARACTER. 
Interior antenne with a moderate pedicle, terminated by 
three seta ; exterior antenne inserted below the internal 
ones, with a large scale at their base, attached to the 
peduncle, with the point unidentate. 
Abdomen with the second joint anteriorly and posteriorly 
produced ; tail with two foliaceous lamelle on each side, 
forming with the middle one a fan-shaped swimming fin. 
Legs ten; two anterior pair didactyle, the anterior pair 
N29 
