CRUSTACEA NORTH PACIFIC EXPLORIAX EXPEDITION 1 85 



rounded within, and its external apex is not produced. The cheH- 

 peds are not broad and depressed, but thick; the hands are about 

 equal, but not large, so that they do not touch each other when the 

 chelipeds are folded against the face. Finall}- the dactyli of the 

 ambulatory feet are of a shape remarkably different from anything 

 yet observed in the family ; instead of the short, thick, curved form 

 observed in all other genera, we have a straight, slender, elongated 

 terminal joint shaped like a stiletto or a flattened needle, and sharplv 

 pointed, but without any indication of a distinct unguiculus. This 

 form of feet is well adapted to the habits of the animal, enabling it 

 to move with facility through the soft mud in which it lives. 

 . It is an inhabitant of moderately deep water, and the only known 

 species is found in the Chinese seas. 



2 2. RAPHIDOPUS CILIATUS Stimpson 



Plate XXII, Fig. 5 



Rapliidoptis ciliatiis Stimpson, Proc. Acad. Nat. Sci. Phila., x, p. 241 

 [79]. 1858. 



Sides of the body and margins of the feet thickly ciliated with 

 long, fine hairs. Carapax pubescent, somewhat areolated ; surface a 

 little uneven, and transversely rugate. Lateral margin strongly con- 

 vex, with a fissure behind the base of the external antennae, two 

 small teeth or spines near the middle, and a spine on the postero- 

 lateral margin at the extremity of a short oblique ridge. Frontal 

 teeth minute, the median one most prominent. Anterior margin but 

 slightly sinuated at the orbits. Latero-inferior regions of the cara- 

 pax strongly striated or longitudinally ridged, especially posteriorly ; 

 ridges few in number and subdistant. The external antennae are 

 four or five times as long as the carapax and folded backwards. 

 Chelipeds large, angular, and very hairy ; meros large, more than 

 two-thirds as long as the carpus, roughened above and armed below 

 with a single long, sharp, curved spine ; carpus about two-thirds as 

 long as the hand, roughened above, with a median longitudinal spinu- 

 lated ridge, its anterior margin not dilated, slightly concave and 

 serrulated ; its posterior margin convex and armed with five spin- 

 ules ; smaller hand elongated, subtriangular. with three longitudinal 

 obtuse ridges, minutely crenulated or spinulated. on the upper sur- 

 face ; fingers longer than the palm, not gaping, tips much curved, 

 crossing each other, inner edges minutely denticulated but not 

 toothed ; inner edge of immovable finger slightly dilated. In the 

 larger hand the dactylus is subcristate above, with a slightly promi- 



