46 ZOOLOGY OE THE VOYAGE OE H.M.S. SAMARANG. 



Thorax trapezoidalis, postice coarctatus. 



Frons prominens, lamellaris, in medio valde incisa. Antennae internee artieulo secundo elongate, 

 usque ad fissuram porrecto. 



Pedes posteriores pedibus Portuno simillimi. 



Abdomen (feminse) articulis septem lateribus subparallelis. Mas adhuc latet. 



External pedipalps with the third joint broader at the base than long, and not notched 

 at its anterior margin near the angle. 



Carapace trapezoidal, considerably contracted posteriorly. 



Front projecting, lamellar, deeply cleft in the middle. Inner antennas with the second 

 joint elongated and reaching to the commencement of the notch. 



Legs very much as in Portunus. 



Abdomen (of female) seven-jointed, the sides nearly parallel. 



This generic group, described from a female, will be found an interesting connecting 

 link between the genera Portunus, Platyonychus, and Polybius. We have named it Poly- 

 bioides from its resemblance to the genus of Leach, which, as Professor Bell remarks, is of a 

 more decided natatory character than any other Brachyurous form found on the British coast. 



1. LISSOCABCINUS POLYBIOIDES, Adams fy White. (Tab. XL Fig. 5.) 



Thorace pentagonali, in fronte producto, postice coarctato, laevissimo, multis parvis rotundatis maculis, 

 linea distincta ab angulo latero-anteriore projecta ; margine latero-anteriore valde dentate, dentibus prorsum 

 inclinatis. 



Fronte lamellari, pro min ente, antiee bifida, antennis lateralibus fronte occultis. 



Chelis artieulo quinto bicarinato ; carina antiee valde dentata. Pedibus posterioribus depressis, pari 

 ultimo unguibus valde dilatatis. 



Hab. Maria Orientalia. 



Carapace five-sided, produced in front, narrowed behind, very smooth on the upper 

 surface, and covered with numerous small round markings, a strong line extending from the 

 latero-anterior angle across the carapace towards the middle line ; latero -anterior margin 

 strongly toothed, the teeth directed forwards. 



Front lamellar, projecting, bifid anteriorly, covering and concealing the lateral antennae, 

 a wide space between the eyes. 



Fore-legs with the fourth joint doubly keeled, the keels strongly toothed anteriorly. 



Hind-legs flattened, the fifth pair with the penultimate joint more flattened than the 

 corresponding joint of the other pairs, and with a greatly dilated flattened claw. 



Hab. Eastern Seas. 



2. LUPOCYCLUS, Adams 8f White. 



Pedipalpi extend artieulo secundo ad apicem tenuiore (quam in Lvpd- — L. forceps), artieulo tertio 

 minore (quam in Lvpd). 



