CRUSTACEA NORTH PACIFIC EXPLORING EXPEDITION 1 63 



SO that the upper surface is concave on either side of the dorsal 

 convexity, which is ahnost carinate along the middle. The front is 

 rostrate ; the rostrum broad and triangular, pointing obliquelx' up- 

 ward. Orbits minute, round, with entire margins. Antennular_\- 

 fossse oblique. External antennae nearly obsolete, or represented 

 only by one or two joints at the base. Epistome sufficiently large. 

 Buccal area as broad as long. Anterior margins of the pterygos- 

 tomian channel entire. Exognath of the outer maxillipeds dilated, 

 as broad as the endognath, its outer margin broadly and regularly 

 arcuated. ]\Ieros-joint of the endognath two-thirds as long as the 

 ischium. Chelipeds with laminiform crests at the edges ; fingers of 

 the hand short. Dactxli of the ambulatory feet very narrow. Ster- 

 num broad. Abdomen of the male narrow-triangular, geniculated 

 near the base (where, however, there is no joint) in a right angle, 

 its segments all confluent \\itli the exception of the first and last. 



This little crab has much resemblance to a Cryptopodia, and in its 

 natural position the main body of the carapax anteriorly is directed 

 obliquely ui)\vard and forward at an angle of 45°. 



263. CRYPTOCNEMUS PEKTAGONUS Stimpson 



. Plate XIV, Fig. 5,6 



Cryptnoicuius f^vitagonus Stimpson, Proc. Acad. Nat. Sci. Phila., x, p. 

 " 162 [60], 1858. 



Carapax much broader than long in the ])rop(jrtion of i: 1.45. 

 The length of the postero-lateral side is one-half that of the antero- 

 lateral. The surface is perfectl}' smooth and glabrous, and convex 

 anteriorly, with a slight longitudinal ridge or carina running from 

 the. tip of the rostrum to the middle of the gastric region. The 

 small cardiac region is slightly prominent. The rostrum is ele- 

 vated to an angle of about (^o' with (ho hi>rizon: tip almost acute; 

 sides convex. The outer maxillipeds and all the lower surfaces of 

 the body are smooth and glossy. The chelijicds are flattened, with 

 glabrous surfaces; the marginal lamina.^ very mucli expanded, tliat 

 of the hand being wider than the slight thickening which constitutes 

 its body, and dee[)ly notched on the outer side near the fingers. The 

 fingers are f)ne-tliir(l a•^ long as ihr ])alin ; iinmnvable finger broad; 

 dactylus sulcated. .Xmbulatory feet crested with lamina?; dactyli 

 very slender. Culur nf preserved specimen white. Dinu-nsions of 

 the cara])a\ in the niak' : Length. 0.2; breadth, o.ji; inch. 



Orrdgc'd from .-^helly nuid in twenty fathoms, in Kagosima i'.a\-. 

 Ja])an. 



