586 PROCEEDINGS OF THE NATIONAL MUSEUM. vol. xxvm. 



CALIGUS BELONES Krbyer. 

 Plate XII, figs. 135-139. 



Female. — Carapace about half the entire length, a little longer than 

 wide. Frontal plates prominent, the anterior margin almost straight, 

 with very little incision at the center. Lunules large and widely sepa- 

 rated, strongly inclined toward the mid line, and subprominent. Pos- 

 terior sinuses wide and shallow, leaving a median lobe less than half 

 the entire width, and projecting but little behind the lateral lobes. 

 Thoracic area about half the dorsal surface of the carapace, well 

 rounded anteriorly. The digestive glands in this area are pear-shaped 

 and inclined toward each other anteriorly. 



Free segment short and strongly contracted where it joins the cara- 

 pace. Genital segment elliptical, one-third the entire length, emargi- 

 nate posteriorly, with short and blunt lobes. Fifth legs not visible 

 dorsally. 



Abdomen elliptical, less than half the width of the genital segment, 

 nearly twice as long as wide. It is contracted to almost half its width 

 where it joins the genital segment. Anal sinus broad and deep. Anal 

 laminae large, one-fourth as long as the abdomen, sublateral, with long 

 plumose setae. 



Egg tubes half the width of the abdomen and a little longer than the 

 carapace, 30 or 40 eggs in each. 



Anterior antennae short, the two joints about the same length, but 

 the terminal joint very slender and closely appressed to the frontal 

 margin. The basal joint is plentifully supplied with plumose setae and 

 the terminal one with spines. 



Second antennae small and short; basal joint nearly as long as the 

 terminal, the angle in the latter very close to the tip. 



Accessory spine large and stout. First maxillae long, slender, and 

 well curved; second pair little more than half as long as the mouth 

 tube, rather slender and blunt at the tip, but much widened at the 

 base. Mouth tube quite stout, a little longer than wide, well rounded 

 at the tip. First maxillipeds slender, the two joints almost equal in 

 length; second pair stout, with a short and blunt terminal claw. Furca 

 long and wide, the base elongate, very narrow, and about as long as 

 the branches, the latter stout and curved into the shape of a horseshoe, 

 of the same diameter throughout. 



Rami of the third pair of thoracic legs well separated, large and 

 prominent; the spine at the base of the exopod slender and nearly 

 straight. The fourth legs are half the length of the genital segment, 

 three-jointed with four spines; basal joint stout and as long as the 

 two terminal joints, which latter are very slender. Second joint 

 longer than the third, with a slender terminal spine; the three ter- 



