1U9. 



75. Head rounded, lips completely amalgamated , » . , « 76 



Head not rounded, lips not completely amalgaraated , . , 78 



76. Tails cylindrical, blunt, more than twice anal body diameter 



,.,.... steatopygous The & Swang., 1936 (a or s) 



Tails nearly hemispherical, length about equal to anal body 



77. Spear length about equal to width of lip region 



e ...... . « teres Th. & Swang., 1936 (marine) 



Spear length about twice width of lip region 



,.,..,.,, . acculeatus Th, & Swang., 1936 (s) 



78. Lips almost continuous with neck contour. . . pacificus Cobb 



Lips set off by a depression or constriction. .,,,»...... 79 



79. Lips set off by a depression 



Lips set off by a constriction 80 



80. Width over 3.0^ , . . varicaudatus Thorne 



Width 2.0^. . alticola Menzel 



81. Tails of both sexes conoid-arcuate. ., 82 



Tails digitate, subdigitate, conoid to hemispherical 112 



82. Tail length 6.0^—15.0^ 83 



Tail length under 5.0^, except 6.0^ in consobrinus 91 



83. Female length over 2,0 mm,j males with four pairs of submedian Cctudal 



papillae ,,, holsaticus Schn., 1925 (a) 



Female length under 1.5 mm.; males without submedian caudal 



papillae ....... 8h 



81i, Head papillae strikingly angular .,,,. 85 



Head papillae not as strikingly angular , 87 



85, Tail length about five times anal body diameter 



angulosus Th. & Swang., 1936 (a) 



Tail length about three times the anal body diameter 86 



86, Body width over 3.0^ humilis Th. & Swang., 1936 (s) 



Body width under 3,0;^ incisus Th, & Swang,, 1936 (s) 



87, Length 0,5 mm. minor Th. & Swang., 1936 (s) 



Length near 1.0 mm 88 



88, Tail subcylindroid to blunt terminus. , . muscorum Skwarra, 1921 (moss) 

 Tail uniformly conoid, apiculate 89 



89, Esophagus with basal pseudo-bulb reisingeri Ditl., 1927 (s) 



Esophagus without basal pseudo-bulb 90 



