THE CRUSTACEA OF NEW JERSEY. 137 



lunate, mostly inclined to central axis, well forward and widely- 

 separated. Sucking-disks small, well anterior, widely separated. 

 Posterior maxillipeds large, well armed. Basal joint of posterior 

 maxillipeds with an oval papillose area, oblique, elevated and 

 covered with short conic spines. Three teeth on hind edge of 

 this joint, stout, acute and long. Second joint with larger papil- 

 lose area on distal end. Third and fourth joints enlarged at 

 distal ends, and whole surfaces below covered with spines and 

 papillae. Terminal joint ends in two curved claws and a fleshy 

 thumb. Swimming-legs all reach well out beyond edge of cara- 

 pace, and two anterior pairs with recurved flagella. Distal joints 

 of all four pairs with a row of plumose setae along posterior edge. 

 Lobes on basal joints of last pair small and well rounded. Tactile 

 papillae at opening of oviduct broad and rather well fused with 

 ventral surface of abdomen. Ventral surface of anterior portion 

 of carapace covered with numerous triangular and rather large 

 spines. 



Color uniform or pale yellowish, slightly deeper along median 

 axis of body, paler about edges. Dorsal surface of thorax with 

 three or four well-defined rows of dark or dusky pigment-spots, 

 strongly contrasted against the yellowish color of the body gen- 

 erally. Length 6 mm. 



Remarks. — A number of examples were secured June ist, 

 1912, by Mr. W. T. Innes, Jr. They were found attached to the 

 fins of gold fish (Carassius auratus) in captivity in Philadelphia. 

 They were removed from the living fish simply by scraping with 

 a small instrument. Among fish fanciers, and those interested 

 in raising gold fish, these parasites are often very annoying. 

 Sometimes they are very difficult to exterminate, and "lousy 

 fish" are never desired by the aquarist. So far as I know it has 

 not yet been found in a wild state in New Jersey, but is often 

 brought into towns and difl:'erent localities by those interested 

 in aquaria. Some fish fanciers claim^ that the Argiilus, evidently 

 this species, also attaches itself to tadpoles (Rana cafesbeiana) 

 when in captivity. 



