1870.] NATURAL SCIENCES OF PHILADELPHIA. 417 



about twice as long as the last joint. Antennal scale narrow, regu- 

 larly tapering, lamellar portion not extending to the spine terminat- 

 ing the external margin. External maxillipeds elongate, extending 

 beyond the antennal peduncle, the last joint with a long pencil of 

 hairs. Larger hand inflated, the upper outer proximal portion cir- 

 cumscribed by an impressed line, a slight constriction of the mar- 

 gins near the articulation of the dactylus ; thumb short, with a 

 shallow groove on the outer surface, which extends a short distance 

 on the palmar portion. Dactylus contorted, extending beyond the 

 thumb, extremity rounded. The dactylus and distal portions of 

 the propodus punctate and setose, especially on the inner surface. 

 Smaller hand subcylindrical, fingers about as long as palm, gaping, 

 tips acute, margins fringed. Carpus of second pair five-jointed, first 

 joint three times, and second twice as long as the third or fourth, 

 which are subequal and slightly shorter than the fifth. The telson 

 regularly tapering, the extremity sinuate-trnncate. The exopodite 

 of the sixth pair of pleopoda (abdominal feet) bears on the ex- 

 ternal distal angle of the penultimate joint, an articulated conical 

 black spine, the color persisting in alcohol, and which will readily 

 separate this from any species with which I am acquainted. Its 

 affinities are with A. sulcatus of Panama and Peru. 



Three specimens from Key West, the largest 25 mm. in length. 



Alpheus heterochelis Say. Specimens were collected at Sara- 

 sota Ba}', Charlotte Harbor, Marcou Pass, Harbor Kej*, and at 

 Northampton County, Virginia, Eastern Shore, Atlantic side ; this 

 last being the farthest north from which the species lias been 

 reported. 



Alpheus paekardii, sp. n. Front, antennulae and antennre as in 

 A. heterochelis except that the sulci between the base of the rostrum, 

 and the ocular hoods are deeper, and last joint of antennular pedun- 

 cle longer than in that species. External maxillipeds short, not 

 reaching to the tip of antennal scale. Chelipeds unequal, meros 

 with an acute tooth on the upper distal angle ; larger hand strongly 

 compressed, with a sharp tooth above near the articulation of the 

 dactylus, beyond this the hand becomes narrower by means of a 

 sharp bend of the inferior margin, dactylus contorted, and working 

 at an angle of about 30 with the plane of the hand. Smaller hand 

 more slender, but similarly ornamented and armed, the dactylus, 

 however, being spatulate, working vertically, and with its margins 

 and those of the opposing thumb densely fringed with hairs. Car- 



