1'). 



Genus Hemicycliophora de Man, 1921 

 (Key to the species) 



1. Annules of lip region distinctly separated. . . . hesperis Raski, 195^3 

 Annules of lip region not separated « ^ » oo o <> = .....,. , 2 



2. Terrainus acute or subacute ^ . . , 3 



Terminus blunt, rounded .......... 22 



3- Length about O.U mm straeleni de Coninck, 1931 



Length 0.7 mm or more li 



l|. Tail long, attenuated 5 



Tail not attenuated 7 



$. Neck cylindroid to truncate lip region 6 



Neck tapering to rounded lip region gigas Thome, 1955 



6. Spear 6l-65u long; body annules 256-263 paradoxa Luc, 1958 



Spear 132u longj body annules about UOO 



micoletzki (Goffart, 19U8) Goffart, 1952 



7. Body slender, a- 33-36 8 



Body more robust, a= 19-26 9 



8. Length 1.0 mm, body arcuate arcuata Thorne, 1955 



Length I.I4. mm, body not arcuate tenuis Thorne, 1955 



9. Body marked by numerous longitudinal striae 10 



Body not marked by longitudinal striae I3 



10. Tail concave conoid 11 



Tail uniformly conoid 12 



11. Lateral fields 1/3 the body width, transversely striated into rectan- 

 gles penetrans Thorne, 1955 



Lateral fields 1/5-1/6 the body width, transversely striated into 

 squares oostenbrinki Luc, 1958 



12. Lateral fields a single line of rectangles. . . penetrans Thome, 1955 

 Lateral fields with a double row of squares . . oostenbrinki Luc, 1958 



13. Cuticle ornamented with delicate longitudinal markings 



aquaticum (Micoletzky, 1913) Loos, 19U8 



Cuticle not ornamented with longitudinal markings lU 



lU. Body tapering rather viniformly from vulva to sub-acute terminus . . 15 

 Body not tapering uniformly, tail concave conoid. . . , 18 



15. Vulva-terminus distance three times spear length, parvana Tarjan, 1952 

 Vulva-terminus distance twice spear length or less 16 



