28 PROCEEDINGS OF THE JSTATIONAli MUSEUM. vol.60 



Genus SAGUM Wilson. 



Sagum Wilson, Proc. U. S. Nat. Mus., vol. 44, 1913, p. 234. 

 Lernanthropus (part) Kk0yeb, Naturhistorisk Tidsskrift, ser. 3, vol. 2, 

 1863, p. 196. 



Generic characters of female. — General body form similar to that 

 of Lernanthropus^ but somewhat shorter and stouter. Cephalothorax 

 angular; antennal area separated from the rest of the head by deep 

 marginal sinuses; lateral margins produced into an angular wing on 

 either side ; posterior body covered with a dorsal plate which is pro- 

 longed at the posterior corners of the third thorax segment into lobes, 

 and which is more or less fused along the median line with the dorsal 

 plate of the fourth segment. Antennae and mouth parts similar to 

 those of Leimanthropus ; first and second swimming legs much re- 

 duced, with one- jointed rami; third legs flattened into laminae which 

 cover the ventral surface and reach back to the posterior margin of 

 the body; fourth legs also flattened into laminae reaching the pos- 

 terior margin, the tips of the rami ending in long flagella. Fifth 

 and genital segments and abdomen reduced and concealed. Egg 

 strings coiled into the space between the dorsal plate and the third 

 and fourth legs and thus entirely concealed. 



Generic characters of male. — Body divided into two sections, 

 cephalothorax and posterior body, each covered with a dorsal plate, 

 the two about the same size. Antennal area separated as in the 

 female. First antennae seven- jointed and prominent; second an- 

 tennae and mouth parts like those of the female. First and second 

 swimming legs rudimentary; third pair with a single ramus in the 

 form of a long cylindrical flagellum; fourth legs like those of the 

 female, each ramus consisting of a basal lamina and a terminal 

 flagellum, the exopod with an accessory flagellum. Genital segment 

 and abdomen not covered, but visible in dorsal view. 



Type of the genus. — Sagum fiagellatum Wilson, monotypic. 



KEY TO THE SPECIES. 



Posterior processe's at the corners of the third segment broad and extending 

 diagonally outward away from the following segments, reaching the pos- 

 terior margin of the dorsal plate fiagellatum Wilson, 1913. 



Posterior processes narrow and pointed, and closely appressed to the sides of 

 the following segments, reaching only halfway to the, posterior margin of 

 the dorsal plate angulatum (Kr0yer), 1863, p. 28. 



SAGUM ANGULATUM (Krwer). 



Lernanthropus angulatus Kk0yeb, Naturhistorisk Tidsskrift, ser. 3, vol. 2, 

 1863, p. 196, pi. 9, fig. 1 Or-q. 



Specific characters of female. — General form short and stout; 

 cephalothorax one-fourth of the entire length, its length and width 

 in the proportion of 5 to 7, with an invagination on either side ante- 



