374 PROCEEDINGS OF THE NATIONAL MUSEUM. ' vol. xxxm. 



Genus DINEMATURA Latreille. 



Caligus (C. productus) Muller, 1785, p. 132. 

 Dinemoura {D. producta) Latreille, 1829, p. 197. 

 Pandarus (P. lamnx) Johnston, 1835, p. 203. 

 Dinematura {D. producta) Burmeister, 1833, p. 284. 



Female. — General body form elongate, the length more than twice 

 the width. Carapace .transversely elliptical, its lateral margins 

 strongly arched, with narrow frontal plates and long well rounded 

 posterior lobes; grooving similar to that in the Caliginge; eyes invisi- 

 ble in the adult. Second thorax segment with large lateral wings; 

 third segment narrow, with rudimentary dorsal plates, or entirely 

 without them; fourth segment with plates of medium size, separated 

 by a deep median fissure, and covering the anterior portion of the 

 genital segment ; fifth or genital segment oblong, with broad and well- 

 rounded posterior lobes; sixth segment distinct, separated from the 

 genital segment, furnished with a pair of dorsal plates, and carrying 

 ventrally a pair of rudimentary swimming legs. Abdomen small, 

 one-jointed, projecting but little behind the genital segment, with 

 large anal laminae, carrying non-plumose setae. 



Two adhesion pads instead of one behind each first antenna, the 

 posterior one the larger. Mouth-tube long and very slender; second 

 maxilloe slender, three-jointed; first maxillipeds with a tuft of setae, or 

 a small setiferous third claw, between the usual two at its tip; second 

 maxillipeds with a stout terminal claw which shuts down between two 

 knobs on the basal joint. 



All the swimming legs biramose; rami of fu'st pair two-jointed, of 

 second and third pairs tlu-ee-jointed, of fourth pair enlarged, laminate, 

 and one-jointed. First tln-ee pairs with plumose setae, fourth pair 

 without setae or even spines. Egg-strings straight and several times 

 the length of the body. 



Hale. — Carapace like that of the female but considerably wider than 

 long; eyes visible and situated far forward. Lateral wings on second 

 thorax segment small; third segment without any traces of dorsal 

 plates; fourth segment with a rudimentary pair overlapping the 

 genital segment a little. Genital segment oblong wedge shaped, 

 widest posteriorly; sixth segment not distinctly separated as in the 

 female, but indicated by an abrupt narrowing of the genital segment, 

 and by notches in its lateral margins. Abdomen very narrow, two- 

 jointed, the joints equal; anal laminjB large and armed with long and 

 stout plumose setae. Appendages like those of the female; first max- 

 illipeds with a tuft of hairs between the two terminal claws, corre- 

 sponding to the middle claw in the female. All the swimming legs 

 biramose; rami of first and foiu^th pairs two-jointed, of second and 

 third pairs three-jointed; first three pairs with long plumose setae, 

 fourth pair with spines only. 



