196 BULLETIN UNITED STATES GEOLOGICAL SURVEY. 



slightly shorter than the second. Basal joint of antennae with a iniuute 

 spine beneath. Antennal scale narrow, reaching slightly beyond an- 

 tennular peduncle, the spine at the antero lateral angle reaching beyond 

 the laminate portion, which is small. External maxillipeds slender, ex- 

 tending to the extremity of the antennal scale, the distal portion with 

 long hairs. Meros of first pair rounded-triangular. Hands small, 

 nearly equal; the larger oblong, compressed, smooth, with scattered 

 hairs; a constriction of both margins posterior to the articulation of 

 the dactylus; fingers completely closing; dactylus acute, shutting into 

 a groove in the propodus, as in the case of A. heterochelis, the tooth of 

 the inner margin being, however, much less prominent. Smaller hand 

 slender, nearly cylindrical, hirsute, the fingers as long as the palm. 

 Carpus of the second pair five-jointed : first joint as long as the three 

 following, second as long as fourth and fifth, third and fourth equal, 

 and together equalling the last. Meros of posterior pairs without spines 

 beneath. Extremity of telson rounded. Panama {F. R.Bradley). Four 

 specimens. 



Alpheus cVlindricus Kingsley. 



Carapax smooth; rostrum very short, obtuse; no orbital spine; first 

 and third joints of antennulss equal, second twice as long. Elagella of 

 antennulse and antennse broken. oSTo spine on basal joint of antennae. 

 Antennal scale slender, narrow, pointed, the laminate portion being 

 almost obsolete, extending to extremity of second joint of peduncle of 

 antennulse. External maxillipeds long, extending beyond peduncle of 

 antennie. Meros of the first pair short, stout, triangular. Larger 

 hand cylindrical, a groove on the outer side below the articulation of 

 the dactylus. Dactylus working horizontally, very short, yet extending 

 beyond the opposable part, two or three teeth on the inner margin, and 

 shutting into a groove in the propodus. Smaller hand cylindrical; 

 fingers as long as palm, equal, slender, curved downward. Carpus of 

 second pair jointed; first joint equalling the following three; second as 

 long as third and fourth, which are equal ; fifth a half longer than fourth. 

 Telson narrow, tapering rapidly; extremity truncate. 



Length of body. Carapax. Larger propodus. Dactylus. 



19.5™™ 8.0™™' 12.0™™ 3.0™™ 



Pearl Island, Bay of Panama {F. H. Bradley). One specimen. 



Alpheus teansverso-dactylus Kingsley. 



Compressed carapax, minutely punctate ; front three-spined ; basal 

 spine of antennulse not extending to the second joint of the peduncle ; 

 second joint twice as long as the third ; inferior branch of flagella twice 

 as long as the superior. Basal joint of antennae with a spine; anten- 

 nal scale very narrow, terminating in a strong spine ; flagella nearly 

 as long as the body. External maxillipeds extending to the tip of the 

 antennal scale; basal joints with scattered hairs; distal joints thickly 



