128 BULLETIN 54, UNITED STATES NATIONAL MUSEUM. 



23. Genus BRANCHUROPUS Moore. 



Peduncle of second pair of antenna? composed of four articles. First 

 pair of antenna? with basal article of peduncle extended straight in 

 front at right angles to remaining part of antenna. 



Maxillipeds composed of two articles; basal article long; second 

 article short, armed with a few hairs. 



Uropods attached to underside of abdomen, similar in structure to 

 the pleopods and probably branchial in function. 



Abdomen with all six segments distinct. 



BRANCHUROPUS LITTORALIS Moore. 



Branchuropus littoralis MOORE, Bull. U. S. Fish Commission, XX, Pt. 2, 1902, 

 p. 168, pi. vni, figs. 13-21; pi. ix, fig. 1. 



Locality. Porto Rico. 



"Body moderately convex, about 2.75 times as long as broad; abdo- 

 men not abruptly narrower than the thorax. Head rounded in front, 

 about half as wide as greatest width of body about two-thirds as long 

 as wide. 



"Thorax broadest at fifth joint fifth and sixth joints longest; the 

 rest shorter and subequal. Epimera of all but first joint distinct; sides 

 of first segment emarginate, the anterior portion being produced some- 

 what to embrace the eye; epimera of second and third segments not 

 produced posteriorly; of fourth, fifth, sixth, and seventh produced in 

 a sharp process terminated by a spine, that of the last extending 

 beyond the first abdominal segment. 



"Abdominal segments all distinct, gradually increasing in length 

 from first to fifth; first segment somewhat narrower, not produced 

 posteriorly at sides, exposed throughout its breadth; the other free 

 segments subequal in breadth, strongly produced posteriorly at sides, 

 the last two armed at each angle with a stout spine. 



"Telson rounded, about five-sixths as long as broad, margin not 

 armed, abruptty higher in median two-thirds at base, with an ill- 

 defined, low protuberance or process on each side of middle line. 



"Eyes large, black, space between about as great as diameter of 

 eye. Base of first antennae projecting from beneath overhanging 

 front; peduncle of three joints, the first and second forming a right 

 angle, the second and third joints subequal; flagellum four jointed, 

 the first joint long and tapering, 1.5 times as long as the other three, 

 second and third joints subequal, last joint short and reaching to 

 beyond posterior margin of head. 



See Moore for characters of genus, Bull. U. S. Fish. Comm., XX, Pt. 2, 1902, 

 pp. 167-168. 



