136 REPORT OF NEW JERSEY STATE MUSEUM. 



Remarks. — Found rather abundantly parasitic on the alewife 

 Pomololms pseudoliarengus, and also said to occur on Osmerus 

 eperlanus and Gasterosteiis aciileatus. In New Jersey limits it 

 has as yet been found only by Rathbun and Wilson, whose ma- 

 terial was obtained at Great Egg Harbor from unknown hosts. 



Argulus trilineatus Wilsou. 



Plate 37- 



Goldfish Louse. 



Argulus triUneata Wilson, Proc. U. S. Nat. Mus., XXVII, 1904, p. 651, figs. 

 34-38. Macon, Georgia (on Carassius auratus). 



Description. — Carapace elliptical, extending well beyond ab- 

 dominal base. Posterior sinus not quite equal to half length of 

 carapace, and a little over twice as long as wide. Antero-lateral 

 sinuses hardly evident. Horseshoe suture long, rather attenuated. 

 First thoracic segment quite short, and all increase in length pos- 

 teriorly till last is several times larger, and thus most of free 

 thorax nearly all exposed. Abdomen spindle-shaped, small, its 

 length one-fourth rest of body and at center its width about two- 

 thirds its own length. Anal sinus excised to center of abdomen, 

 narrowly uniform, and papillae small, basal. Both antennae rather 

 weak, small, and rather well furnished with hooks and spines. 

 Anterior and lateral hooks on basal joint of first antennae slender, 

 and spine on hind border large. End of first antennae slender, 

 not extending beyond lateral hook. Basal joint of second an- 

 tennas equals, though much thicker than two terminal joints, and 

 latter attached obliquely to one of its distal corners, thus two 

 portions of antennae stand nearly at right angles to each other. 

 Basal joint with stout spine on its hind edge, where joining head, 

 and two long ventral slender spines at distal end. Second joint 

 with single long spine on front edge at distal edge, while terminal 

 joint with five or six large stout spines. Spines along either side 

 of median line of body opposite bases of antennae, those on hind 

 edge of basal joints of antennae and lateral hooks on first antennae 

 yellow, and all others colorless and transparent. Eyes small, 



