16 



BULLETIN 15 8, UNITED STATES NATIONAL MUSEUM 



Figure 4. — Argulus laticauda: a. Female, dor- 

 sal ; 1), supporting ribs of sucking disk 



Female. — Carapace elliptical, longer than wide, lateral lobes 

 usually reaching the urosome ; posterior sinus twice as deep as wide. 

 Urosome orbicular, a little longer than wide, cut less than a quarter 

 of its length, caudal rami basal. Anterior legs with flagella. Teeth on 

 basal plate of maxillipeds broadly laminate and squarely truncated ; 



respiratory areas very unequal 

 in size, the smaller one anterior 

 but touching the larger; each 

 supporting rod of the maxilla- 

 ry disks short and threadlike, 

 made up of 4 segments. Total 

 length, 5-7 mm. Width of 

 carapace, 3-4 mm. 



Male. — Nearly as large as 

 the female, with the same 

 shape and proportions; basi- 

 pod segments of second and 

 third legs with fleshy poste- 

 rior lobes, the distal ones narrow and fingerlike, the proximal 

 ones broad and rounded; basipods of fourth legs with the regular 

 boot-shaped lobes; peg short and rather blunt. Total length, 4-Q 

 mm. Width of carapace, 3-4 mm. 



Remarks. — This species may be recognized at once by its dark 

 color, and it is often found in considerable numbers on the two 

 flounder hosts. 



ARGULUS MEGALOPS Smith 



Figure 5 



Argulus megalops Smith, Rep. U. S. Comm. Fish and Fisheries, 1872-73, p. 575, 

 1873.— Rathbun, Proc. U. S. Nat. Mus., vol. 7, p. 485, 1884.— Wilson, Proc. 

 U. S. Nat. Mus., vol. 25, p. 706, pi. 11, figs. 10-13, 1902. 



Host and locality. — Outside surface of winter flounder, Pseudo- 

 pleuronectes americanus; summer flounder, Pa/ralichthys dentatus; 

 sand dab, Hipfoglossoides 'platessoides ; spotted flounder, Lo'phop- 

 setta maculata; sea robin, Prionotus carolirms; long-horn sculpin, 

 Myoxocephalus octodecimspinosus ; goosefish, LopMus piscatorms, 

 and in surface tow, all in the Woods Hole region. 



Distribution — Not found thu^ far outside the present area. 



Color. — Body yellowish or grayish with four pale-brown longi- 

 tudinal stripes; entire upper surface of urosome in fully developed 

 females reddish or pinkish brown, thickly sprinkled with minute 

 black dots. Each lateral lobe of the carapace contains a branched 

 design in black pigment; eyes, semen receptacles, and testes dark 

 brown, almost black. 



