456 PROCEEDINGS OF THE NATIONAL MUSEUM vol. 115 



Betaeus harfordi MacGinitie and MacGinitie, 1949, p. 279 (part). — Ricketts and 

 Calvin, 1952, pp. 323-324. 



Female. — Carapace laterally compressed but no carina. Smooth 

 but with scattered short setae. Tuft of longer setae under front, be- 

 tween eyes; cardiac notch and lower posterior margin fringed with 

 setae. Front (fig. 52) deeply indented medially, slightly depressed 

 but produced laterally to form "blister" over each eye. Anterior 

 margin (fig. 53) smoothly curved. Anterolateral junction rounded. 

 Lateral margin evenly rounded with widest part at base of first legs. 

 Posterior margin somewhat truncate with distinct cardiac notch. 



Abdomen rounded, with posteroventral margins of pleura rounded 

 in segments one to thi-ee but angled in four and five. Ventral margin 

 of first segment with plumose setae. Smooth with scattered setae. 



Telson (fig. 68) longer than sixth segment and about 1% times 

 as long as widest part. Dorsal surface with scattered setae and 

 two pairs of movable spines. Posterolateral angle with two spines: 

 inner much larger than outer. Posterior margin rounded with bristles 

 and plumose setae. 



Eye large, round, and with sharp tooth on stout eyestalk. 



Antennule with well-developed stylocerite; slender, sharp-pointed, 

 reaching nearly to end of second segment of peduncle. First segment 

 of peduncle produced ventrally into thin sharp tooth. Middle joint 

 of peduncle nearly twice as long as first or third joints, whole peduncle 

 more than K as long as carapace. Inner flagellum slender, about 

 as long as carapace. Outer flagella fused for )^ its length, with long 

 sensory setae, and terminating in short free part and long slender 

 flagellum. 



Antenna with fu-st segment of peduncle produced ventrally into 

 sharp tooth. Scale (fig. 57) slender; spine large, longer than blade, 

 separated from slender blade for nearly }^ its length. Peduncle only 

 slightly longer than that of antennule. Flagellum twice as long as 

 carapace: flattened oval in cross section. 



Third maxilliped with ischiomeropodite broad, flattened proximally, 

 twisted. Inner margin heavily bristled, outer sparsely. Penultimate 

 segment K length of distal segment, with bristles mainly on inner side. 

 Distal segment nearly as long as ischiomeropodite, armed medially 

 with rows of stiff bristles; reaches to end of antennular peduncle. 

 Exopodite longer than ischiomeropodite. 



Fu'st legs subequal in size. Ischium short, with sharp ridge 

 ventrally. Merus short, stout, triangular in outlme: dorsal ridge 

 sharp, covered with soft setae; outer ridge undulate with knobs 

 on proximal part, inner ridge tuberculate for most of its length. 

 Broad oblique groove in which second leg rests. Distal margins of 

 merus concave on inner side of median ridge. Joint membrane large, 



