606 PROCEEDINGS OF THE NATIONAL MUSEUM. vol. xxvra. 



CALIGUS HffiMULONIS KrOyer. 

 . Plate XV, figs. 180-183. 



Caligus hxmulonis Kroyer, 1863, p. 48, pi. rv, fig. 3, a-d. — Bassett-Smith, 

 1899, p. 448. 



Female. — Carapace not quite half the entire length (as 9 to 20), as 

 wide as long-. Frontal plates projecting very strongly between the 

 lnnules, with a deep median incision. Lunules themselves large, ellip- 

 tical and widely separated. Posterior sinuses wide and shallow; 

 median lobe a little more than half the entire width, and projecting 

 but little behind the lateral lobes; the latter broad and well rounded. 

 Cephalic area very much larger than the thoracic; eyes over the base 

 of the proboscis and elliptical. Free segment very narrow and short, 

 standing out in sharp contrast with both carapace and genital segment. 



Genital segment orbicular or slightly obcordate, a little wider than 

 long with a shallow posterior emargination. It is one-third shorter 

 than the carapace with symmetrically rounded sides and posterior 

 corners. 



Abdomen a little more than half as long as the genital segment and 

 one-third as wide, contracted at its base and unsegmented; anal papilla? 

 small with short seta?; egg strings unknown. 



First antennae small, the joints equal in length; second pair situated 

 so near the posterior border of the lunules as to partially hide them. 

 First maxilla? stout and sickle-shaped; second pair a little shorter than 

 the proboscis, situated far forward on either side of the latter and just 

 reaching its tip. 



They are simple, somewhat weak, acuminate and slightly curved. 

 Maxillipeds of the usual form; furca large, base as long as the branches, 

 with parallel sides and an oval foramen; branches stout, acuminate, 

 curved, divergent, the space between them having a width equal to its 

 length. First swimming legs short and thick, the terminal spines all 

 the same length, while the plumose seta? on the posterior border of the 

 terminal joint are entirely lacking. Rami of third legs widely sep- 

 arated, the outer branch long and stout. Fourth legs three-jointed, 

 the basal joint as long as both the others, minus the claws; second and 

 third joints the same length; claws quite close together. 



Total length 2.8 mm. Length of carapace 1.35 mm.; width of the 

 same 1.3 mm.; length of genital segment 0.75 mm.; length of abdo- 

 men 0.6 mm. 



No statement with regard to the color or habits. 



Male. — Carapace slightly more than half the entire length; frontal 

 plates distinct, not projecting as in the female, but about as deeply 

 incised at the center. Lunules large and more nearly circular. Pos- 

 terior sinuses even more shallow than in the female; median lobe con- 



