CRUSTACEA OF ALABAMA. 19 



Harpacticus chelifer, Mueller. 



(Plate II, Figs. 15, 17, 19, 20, and Plate VI, Fig. 5.) 



Cyclops chelifer, O. F. Muelllr, Prodr , 1776; Entomos., 1785. 

 Cyclops armatus, Tieesius, Mem. Acad. St. Petersb , 181 2. 

 Arpactkus chelifer, Baird, Brit. Entom., 1840. 

 Harpacticus chelifer, Claus, Freileb. Copepod. 1863. 

 (var.) Harpacticus gracilis, Claus, Freileb. Copepod. 1863. 

 (var. ) Harpacticus niccensis, Claus, Copep. v. Nizza. 1866. 

 Harpacticus elongatus, Boeck. 

 Harpacticus chelifer, var? Herrick, Final Rep., 1884. 



Our species agrees most closely in several respects with the variety called by Claus, 

 H. gracilis, but seems intermediate, in several respects, between it and the typical H. 

 chelifer. The poverty of material at our disposal makes it wiser to accept the conclusion 

 of later writers that these species are identical and leave the exact relations to later ob- 

 servation. 



Body moderately long, anterior segment nearly as long as the following three, 

 abdomen comparatively short (in our form apparently rather longer than in the type,) 

 second and third abdominal segments united in the female and thickened, the last seg- 

 ment and the caudal stylets short, all the abdominal segments with spinous armature be- 

 low ; antenna; of the female slender, with a slender styliform appendage from the long 

 fourth joint, male antennae with the third and sixth segments largest, the latter being 

 greatly swollen, the following three joints small and forming a prehensile organ ; anten- 

 nules short, two-jointed, terminal segment with four geniculate and three straight setae, 

 palp minute, two-jointed ; mouth parts with the generic characters ; second maxilliped 

 dactylate, with a toothed excavated portion to oppose the claw ; first foot with both rami 

 two-jointed, the other being greatly elongated and both spiny margined and clawed ; the 

 other feet with both rami three-jointed ; fifth foot of male with the second joint narrow, 

 with five nearly apical setae, that of the female oval, with five setae, while its basal joint 

 is expanded within and bears three or more spines. 



Length of entire animal somewhat under 1 mm. Mississippi sound and other parts 

 of Gulf of Mexico, not found in rivers. The ova are frequently very numerous and are 

 bourn by the female in a discoid mass beneath the abdomen. 



GENUS LAOPHONTE, Philippi. 



Body more elongate than Harpacticus, especially the abdomen, segments angular, 

 often with spinous armature sometimes amounting to enormous processes ; antennae 4- 

 to 8-jointed, modified in the male as in Harpacticus ; antennules often relatively large, 

 with minute palp ; palp of mandible small ; maxillae well armed with a considerable palp; 

 second maxilliped dactylate, slender ; first pair of feet with the longer branch 2-jointed, 



