COPEPODS OF THE WOODS HOLE REGION 621 



69. Annulus terminal at anterior end of an ovoid, symmetrical 



body; ovisacs spindle-shaped, four times as long as wide; 



on annelids 9 Saccopsis Levinsen, 1878 



Body squarely truncated at both ends; annulus ventral, nearer 

 anterior end; ovisacs cylindrical, eight times as long as wide; 

 dredged, 8 fathoms (see p. 603) 9 Jeanella T. Scott, 1904 



Body rounded at one or both ends; annulus ventral, nearer pos- 

 terior end; ovisacs ovoid, twice as long as wide 70 



70. Head fused with tissues of host; neck short, stout; annulus 



thick; trunk enlarged at each posterior corner, with ovoid 



ovisacs; on annehds ? Herpyllobius Steenstrup and Liitken, 1861 



Head capable of separation from tissues of host and furnishing 



important diagnostic characters 7L 



71. Head clavate, with fleshy expansions; neck short and stout; 



trunk laterally compressed and evenly rounded posteriorly; 



on annelids ? Hedyphanella Leigh-Sharpe, 1926 



Head mushroom-shaped; neck curved, elongate; trunk bilobed 

 posteriorly, 1 ovisac issuing from each of the lobes; on 

 annelids 9 Phallusiella Leigh-Sharpe, 1926 



72. Trunk of female ovoid; head unknown; neck terminal, very 



thick; each ovisac hemispherical, much larger than trunk; 



on anneUds ? Bradophila Levinsen, 1878 



Trunk of female ovoid or spherical; neck ventral and nearer pos- 

 terior end of trunk ^^ 73 



73. Head expanded and flattened with crenate edges, concave 



anteriorlj'; neck short, filiform; trunk without lobes; on 



anneUds ? Herpyllobius Steenstrup and Ltitken, 1861 



Head unknown; neck short and very stout; annulus thick; 

 trunk with 2 spherical lobes at posterior end; on annelids. 



9 Sarsileniura Leigh-Sharpe, 1926 



74. Trunk of female napiform; head terminal, rhizoid; neck slender, 



fused with head; no annulus; ovisacs spherical; on crustacea. 



9 Rhizorhina Hansen, 1892 

 Trunk subtrapezoidal or saccate; head unknown; neck ventral 75 



75. Trunk depressed; neck nearer anterior end; ovisacs reniform 



and turned forward along sides of trunk; on annelids. 



9 Eurysilenium M. Sars, 1870 

 Trunk swollen; neck nearer posterior end; ovisacs cylindrical, 

 extending straight backward, longer than trunk; on annelids. 



9 Eurysileniopsis Gravier, 1912 



76. Trunk transversely semilunar, concave side fused with wall of 



host's alimentary canal; no head, neck, or annulus; on 



annelids 9 Aphanodomus Wilson, 1924 



Trunk cylindrical, one end fused with host, alimentary canal 

 of copepod opening into that of annelid; hermaphroditic; 

 on annelids 9 Xenocoeloina CauUery and Mesnil, 1915 



77. Body folded into an unsegmented ellipsoid; head separated, 



with a minute carapace; basal segments of maxillipeds com- 

 pletely fused; flesh of fishes cf Sphyrion Cuvier, 1830 (p. 530) 



Body not folded, head and trunk in same line or curve and 



more or less distinctly segmented 78 



71937—32 41 



