134 REPORT OF NEW JERSEY STATE MUSEUM. 



Sub-Order BRANCHUIRA. 



Body flattened, consists of shield-shaped cephalothorax in 

 which first thoracic segment is fused with head, a free thorax 

 of three segments, and a two-lobed abdomen without segments. 

 Four pairs of swimming-feet, long and furnished with two rows 

 of plumose setae. Two large compound eyes, movable and 

 surrounded by a blood sinus. Testes in abdomen. Heart present. 

 Females without ovisacs. Eggs attached to foreign objects. 

 Ectoparasitic. 



These include the highest type of parasitic copepods, attach- 

 ing themselves to their hosts or leaving them at will. 



Family ARGULID^. 



Characters expressed above. 

 A single genus in our region. 



Genus ARGULUS Miiller. 



Argulus Miiller, Entomostr. Dan. Norweg., 1785, p. 121. Type Argidus charon 



Miiller, first species. 

 Ozolus Latreille, Hist. Nat. Crust., IV, 1802, p. 128. Type Osolus gasterostei 



Latreille. monotypic. 



A sheathed stylet or sting in front of mouth, used for a pierc- 

 ing organ. Anterior maxillipeds transformed into sucking-disks. 

 Posterior maxillipeds armed with setae, spines and chitinous plate 

 on basal joint. This plate elevated above surrounding surface 

 and roughened by spines or warts, and prolonged into three 

 sharp spines in its hind border. Two pairs of antennae, an- 

 terior armed with stout sickle-shaped hooks and function as 

 organs of prehension. Basal joints of posterior swimming-legs 

 usually prolonged into lobes projecting beneath abdomen. 



Kc\ to the species. 



a. Carapace elliptical, longer than wide ; general color yellowish and not 

 variegated much or with brilliant tints. 



b. No dark pigment spots on dorsal face of thorax. alosar 



bb. Three rows of dark or dusky pigment spots on dorsal face of thorax. 



trilineata 



