PARASITIC COPEPODS — WILSON 559 



mentary specimens, including both sexes, from goldfish at Yokohama 

 and gave a more detailed description. More recently specimens, also 

 including both sexes, were taken from goldfish at Tokyo and sent to 

 the National Museum. They differ from Thiele's in a few details. For 

 this reason, and more especially to afford a ready means of comparison 

 between this species and A. hmatus, the Tokyo specimens are here 

 described and figured. 



Fern-ale. — Carapace circular, as wide as long and reaching just be- 

 3^ond the anterior margin of the fourth thoracic segment, the rami of 

 the first three pairs of legs and nearly all of the fourth pair being 

 visible dorsally. Compound eyes of medium size, far forward and 

 well separated; median eye farther back and very small. Anterior 

 ends of the median ribs distinctly forked, the cephalic area much 

 longer than wide. Second and third thoracic segments much wider 

 than long, fourth segment narrower, with a constriction at the center 

 of each lateral margin. Abdomen elliptical, one-half longer than wide 

 and contracted into a short neck where it joins the thorax. Posterior 

 sinus narrow and V-shaped, less than a quarter of the abdomen length, 

 the caudal rami basal, the posterior lobes short and broadly rounded. 

 Basal portion of the first antenna short with a curved and bluntly 

 rounded spine on its inner margin. Second segment with a stout, 

 acute spine on the anterior margin, a curved acute spine on the ventral 

 surface near the posterior margin and a slender lateral claw curved 

 into a half circle. Second antenna 6-jointed, the basal joint enlarged 

 and armed with a long blunt spine at its inner end. The five terminal 

 segm.ents are each about the same length and extend well beyond the 

 tip of the first antennae. The maxilliped is fairly stout, its basal plate 

 with a raised knob covered with spines on its ventral surface and three 

 long acuminate posterior spines. There are no flagella on the swim- 

 ming legs and the basal segment of the fourth leg has a small semi- 

 circular flap on its posterior margin. Each supporting rib in the 

 margins of the sucking disks is made up of nine small segments like a 

 row of beads, all about the same size, and the fringe on the margin is 

 a row of flattened spatulate laminae with bluntly rounded tips. Total 

 length, 6 mm. Carapace, 4 mm. long. 



Male. — Considerably smaller than the female, the carapace just 

 reaching the abdomen and leaving less of the legs visible in dorsal 

 view. Abdomen more regularly elliptical in outline and the posterior 

 sinus a little deeper. The testes are elongate-ovate and tapered back- 

 ward and extend into the posterior lobes. 



The antennae and mouth parts are similar to those of the female ; in 

 the second legs the proximal segment has two large knobs covered 

 with small spines projecting from the posterior margin. In the third 



