482 



BULLETIN 15 8, UNITED STATES NATIONAL MUSEUM 



C^y^ 



Color. — Head blood red; neck and horns cartilage gray; trunk 



and egg strings brownish yellow. 



Female. — Head bent forward at right angles to the thorax, with 



four attachment plates on the anterior margin (forehead) in front 



of the antennae. One pair of long branched lateral horns at the 



posterior margin of the head; an- 

 other pair of lateral horns and an 

 unpaired dorsal horn, all three dich- 

 otomously branched, on the thorax 

 behind the fourth legs. Neck longer 

 than the trunk and abdomen com- 

 bined, flexed behind the horns and 

 again where it joins the trunk, where 

 also it is slightly enlarged. Trunk 

 a short ellipsoid, flattened laterally ; 

 abdomen three-fifths as wide and 

 nearly as long as the trunk. First 

 antenna 3-segmented; second anten- 

 na 2-segmented, chelate; first three 

 pairs of legs with a single ramus in- 

 distinctly segmented; fourth legs 

 made up of the basal plates only, 

 without rami. Total length, 10-12 

 mm. Egg strings, 8.5 mm. long. 

 Remarks. — This species can be identified by the branched horns 



and the attachment plates on the head ; thus far it is confined to the 



single host. 



LERNAEENICUS AFFIXUS Wilson 

 FiGXJBB 289 



Lernaeenicus affixus Wilson, Proc. U. S. Nat. Mus., vol. 53, p. 64, pi. 6, 1917. 



Occurrence. — Fastened to a bone or a bony fin ray in the tomcod, 

 the mummichog, the white perch, and the blueback {Pomolohus 

 (lestivalis) ., all caught in or around Woods Hole. 



Distribution. — Not found outside the present area. 



Color (preserved material). — Body a uniform light orange-yellow; 

 the head, neck, and egg strings brownish; the trunk often spotted 

 with brown. 



Female. — Head turned ventrally at right angles to the thorax, with 

 four attachment plates on its anterior surface; no horns on the 

 head, but a single pair, short and unbranched, on the sides of the 

 thorax behind the fourth legs. Rarely these horns are branched, 

 or there are two pairs close together. Neck slender, widening gradu- 

 ally at its posterior end into the trunk, which is longer than the 

 neck and from ten to fifteen times as wide. The abdomen is three- 



FiGDRB 288. — Lernaeenicus polyceraus: 

 a, Female, lateral ; h, female, one of 

 each of the four pairs of legs 



