COPEPODS OP THE WOODS HOLE REGION" 15 



Color. — Entire body a light sea green, faintly washed with yellow ; 

 eyes, semen receptacles, testes, and outlines of respiratory areas light 

 cinnamon-brown. Male often light grayish brown without any tint 

 of green ; eyes brownish black, brain purple, testes covered dorsally 

 with small circular purple spots ; ventral surface of each testis with 

 a longitudinal line of dark purple through the center, forked at the 

 posterior end. Ventral surface of thorax and basipods of legs 

 covered with small spots of brick red. 



Female. — Carapace orbicular, wider than long, its lateral lobes 

 usually overlapping the base of the urosome, but sometimes not 

 reaching it; two anterior pairs of legs with flagella. Urosome rela- 

 tivel}^ very small, orbicular, about as wide as long, cut one-third of 

 its length, caudal rami basal ; teeth on basal plate of maxilliped very 

 wide and blunt, often only two in number. Smaller respiratory 

 area set into the inner margin of the larger one near its center. 

 Each supporting rib in the margins of the maxillary disks made 

 up of 7 elliptical basal segments, 3 S-shaped segments, and a terminal 

 crescentic segment. Total length, 10-12 mm. Width of carapace, 

 about 11 mm. 



Male. — Urosome relatively longer than in the female, one-third 

 as long as the carapace ; both basipod segments of fourth legs with 

 a posterior flap; peg long and slender; proximal basipod segment 

 of third legs transversely semilunar, posterior end a wide bluntly 

 rounded flap, anterior end tapered to an acuminate point ; proximal 

 segment of second legs with two small flaps, one dorsal and one 

 ventral, at its distal posterior corners. Total length, 5-6 mm. 

 Width of carapace, 4—5 mm. 



Remarks. — This is the oldest of our American argulids and is 

 much the largest of those found in the Woods Hole area. 



ARGULUS LATICAUDA Smith 



Figure 4 



Argulus laticauda Smith, Rep. U. S. Comm. Fish and Fisheries, 1872-1873, 

 p. 574, 1873.— Rathbun, Proc. U. S. Nat. Miis., vol. 7, p. 484, 1884.— 

 Wilson, Proc. U. S. Nat. Mus., vol. 25, p. 705, pi. 10, figs. 5-9, 1902. 



Host and locality. — Outside surface of the eel, Anguilla rostrata; 

 the winter flounder, Pseudo-pleuronectes americanus ; the summer 

 flounder, Paralichthys dentatus; the tomcod, Microgadus tomcod; 

 the sculpin, Myoxocephalus soorpius, all at Woods Hole, Mass. 



Distribution. — Never reported outside the Woods Hole region. 



Color. — Body yellowish mottled with thick black pigment ar- 

 ranged in more or less radiating spots and bands, often so confluent 

 as to make the copepod almost a uniform black. Pigment sometimes 

 reddish brown or even purple, especially in smaller specimens. 



