486 



BULLETIN 15 8, UNITED STATES NATIONAL MUSEUM 



LERNAEOCERA BRANCHIALIS (Linnaeus) 



Figure 292 



Lernaea tranchialis Linnaeus, Systema naturae, ed. 12, vol. 1, p. 1092, 1767. 

 Lernaeocera hrancMaUs Wilson, Proc. U. S. Nat. Mus., vol. 53, p. 85, pis. 10, 12. 

 17, 1917. 



Occurrence. — Fastened to the gill arches of the common cod, cap- 

 tured in and around Woods Hole. 



Distribution. — European coasts (Linnaeus, Miiller, Blainville, 

 Nordmann, Kr0yer) ; British Isles (Baird, Thompson, T. and A. 

 Scott) ; Greenland (Steenstrup and Liitken) ; Iceland (Hansen) ; 

 Denmark, Sweden, Norway (Kr0yer, Hansen) ; coast of Maine 

 (Wilson). 



Color. — Body dark reddish brown, becoming yellow in preserva- 

 tives ; horns dark brown ; ^gg strings orange-yellow. 



Female. — The dorsal horn longer 

 than the lateral ones, all three pro- 

 fusely branched, the tips of the 

 branches usually swollen. Neck often 

 wrinkled transversely; trunk consid- 

 erably elongated and bluntly rounded. 

 Head turned forward at right angles 

 to the neck, so that the proboscis when 

 protruded is parallel with the axis 

 of the neck. The first two pairs of 

 legs are close together, the third and 

 fourth pairs are separated a little, 

 the fifth pair is obsolete. Total length, 

 30-40 mm. Egg strings, 150-200 mm. 

 long. 



Remarhs. — If found at all the males will be only 1 mm. long and 

 perfectly free, darting about over the gill filaments of their host. 

 They have been found on the gills of the plaice and the lumpfish 

 in European waters but have never been reported from our American 

 shores. They must be present, however, upon some convenient host, 

 and will probably be found in the near future. The female can be 

 recognized by its large size and the S-shaped curve of the trunk. 



Genus LERNAEOLOPHUS Heller, 1865 



Female. — Head fused with first segment and turned forward at 

 right angles to the neck axis, and armed with three horns, one dorsal 

 and two lateral. Neck cylindrical, stout, attached to the trunk on 

 the midline, and showing more or less torsion. Trunk bent in a 

 sigmoid curve, the walls of both neck and trunk heavily chitinized ; 



5 mm. 



Figure 292. — Lernaeocera hranchialia : 

 a. Female, lateral (drawn by 

 Blake) ; b, female, horns, dorsal 

 view 



