COPEPODS OF THE WOODS HOLE REGION 613 



79. Egg strings looped in loose masses; horns long and branched 80 



Egg strings tightly coiled into regular spirals; horns varying 81 



80. No abdominal processes; trunk bent in a regular sigmoid curve; 



cephalic horns very irregular; first antennae 3-segmented; 



gills of fishes 9 Lernaeocera Blainville, 1822 (p. 485) 



Five or six processes along each side of abdomen; trunk simply 

 curved; horns regularly branched; first antennae 2-segmented; 

 gills of fishes 9 Lernaeolophus Heller, 1865 (p. 486) 



81. Cephahc horns branched; abdomen as long as trunk, with many 



lateral processes; neck very short, nearly obsolete; gills of 



fishes 9 Haemobaphcides T. and A. Scott, 1913 



Cephalic horns unbranched; abdomen half as long as trunk, 

 without lateral processes; neck much longer than trunk; 

 flesh of fishes 9 Trifur Wilson, 1917 



KEY TO THE GENERA OF THE SUBORDER LERNAEOPODOIDA 



(The swimming legs are entirely absent in more than half of the genera of this 

 group, and hence distinctions must be based largely upon the relative size 

 and shape of the body regions and upon the structure of the antennae and 

 maxillae) 



1. Parasite fastened to its host by its second antennae, second 



maxillae, or maxiUipeds, or by combinations of two or more 



of these 2 



None of the regular appendages used for attachment, but the 

 parasite buries its head and neck in the tissues of its host 60 



Parasite not fastened to its host, but lying free within certain 



canals, sinuses, or glands, or in the flesh of its host 82 



Parasite not fastened to its host, but lying inside a gall within 

 the body of the host; antennae and mouth parts present, but 

 no legs; in sea urchins cf 9 Pionodesmotes Bonnier, 1898 



2. Second antennae nonprehensile or lacking; second maxillae 



uncinate, serving with the maxillipeds for attachment to the 



host 3 



Second antenna prehensile; second maxillae nonprehensile; 2 



posterior pairs of legs modified or lacking 9 



Second antennae nonprehensile; second maxillae fused at their 



tips, with a prehensile bulla; adults without legs 25 



Second antennae modified into tripartite horns; second maxillae 

 and maxillipeds uncinate; 4 pairs of leg rudiments; gills of fishes. 



9 Trichthacerus Kr0yer, 1863 



3. Abdomen 1-segmented; first antenna indistinctly segmented; 



2 pairs of birarhose legs, rami 1-segmented; no ovisacs; head 

 fused with the trunk; marsupium of amphipods. 



cf 9 Stenoth.och.eres Hansen, 1897 

 Abdomen lacking, but caudal rami often present; 2 pairs of 



swimming legs present, uniramose and 1-segmented 4 



4. Genital area present; genital apertures close together, their chitin 



rings more or less fused 5 



Genital area lacking; genital apertures widely separated, rings 



not fused; second antennae, legs, and caudal rami lacking 8 



