120 CRUSTACEA. 



outer antennae narrow anteriorly, the outer angle prolonged into a spine, 

 which is usually obtuse. Cavity of the inner antennae with the pos- 

 terior margin obliquely sloping forward towards the cavity, and the 

 outline of the whole, this part included, elliptical. Exterior maxil- 

 lipeds with the third joint subtriangular, the outer anterior angle 

 being prolonged outwards much beyond the line of the outer margin 

 of the second joint, and subacute. 



In the males (with one exception ?) the abdomen is quite narrow ; 

 the penult segment is longer than the preceding, and has a low salient 

 angle on its opposite sides. 



Hand of the first pair of legs, with the fingers either in contact 

 throughout, or only at the extremity ; inner margins wholly or partly 

 denticulate ; in some males, a broad tooth near articulation. 



Area either side of mouth with the margin bidentate. 



MENJSTHItrS ANGUSTUS. 



Carapax sat tuberculatw, perangustus (latitudine multo minore quam 

 longitudo post-rostralis) , dentibus lateralibus tribtis, duobtts anticis 

 bilobatis ; rostro longo, emarginafo; regiot^e mediand tumidd, postice 

 bituberculatd et anterius ared triangulafd iwtata ; regione post-mediand 

 brevi, unituberculatd ; regione intestinali grandi unituberculatd, mar- 

 gine postico rotundato, integro. 



Carapax tuberculous, quite narrow (greatest breadth much less than 

 length of post-rostral part), lateral teeth three, the two anterior bilo- 

 bate ; beak long, emarginate, medial region tumid posteriorly, having 

 two small tubercles, and just anterior to them an area slightly promi- 

 nent of a triangular shape, post-medial region short, unituber- 

 culate, intestinal region large, with one tubercle, posterior margin 

 of carapax rounded, entire. 



Plate 4, fig. 5 a, carapax, enlarged three diameters ; Z, under view of 

 mouth, &c., enlarged six diameters. 



Locality doubtful. Expedition collections. 



Length, five and one half lines; greatest breadth, three lines ; length 



