5 Collar setae include stout bayonet-setae with conical bosses 



at base of smooth blade 6 



5' Collar setae all winged capillaries with smooth or serrated 



blades. [Operculum chitinous. either conical or cylindrical] 13 



6 Operculum a simple funnel formed of fused radii. (S'-rpnla) 



[Inner surface of funnel minutely granular] S. ro'Diiciihiris gjxniulosa 



6' Operculum of two parts: a basal funnel of fused radii and an 

 upper crown of 8-14 horny spines. (Hiidroides) [Tips of radii 

 ending in simple points] 7 



7 Opercular spines with one or more pairs of lateral spinules; 



[tips curved inwards] 8 



7' Opercular spines without latei'al spinules 10 



8 Opei'cular spines with 2-3 pairs of lateral spinules. Bayonet- 



setae with denticulate shaft -heads. Tube attached to floating 



objects {H. elegaiis) No N.C. record 



8' Opercular spines with one pair of lateral sjiinules. Bayonet- 

 setae with shaft-heads smooth apart from the two conical 

 bosses 9 



9 Opercular spines equal in size H. criicigcra 



9' Opercular spines unequal; [often knobbed at point of in- 

 flection ] H. pitrva 



10 Tips of opercular spines all curved inwards toward center 11 



10' Tips of opercular spines not all curved inwards toward center 12 



11 Oi)ercular spines graded in length. Many spines with an exter- 



nal conical spinule near base H. saiictaernicis 



11 ■ Opercular spines equal in length. All s]:)ines with an inner 



hooked spinule near base H. Kiiciiiatns 



12 Tips of spines curved in same direction, some pointing in- 



wards, some sideways, and some outwards H. dicnithiis 



12' Tips of spines curved outwanls. [Tips of radii curved out- 

 wards] H. pri)tiilirola 



V.\ Opercular stalk annulated, replacing second dorsal radiole on 



left side. Operculum without internal .septa. CJauge of 



uncinus simple (J\I( hircniiilid) M. nmltici-isldta 



i;V Opercular stalk wrinkled, replacing first dorsal radiole on 



right side. Operculum truncate with internal .septa and 



external rings. (lauge of uncinus hifui-cate {]'( i-niiliopsis) T'. uinmlala 



14 Shell coiled anticlockwise when seen from above. Incuba- 

 tion in tube. Collar setae without a (in at base of blade Spirorhis (Circcis) .^7>//////nH 



14' Shell coiled anticlockwise when seen from above. Incuba- 

 tion in operculum. Collar .setae with a fin at base of blade .... Spirorhis (JtuiuuJ cun-ugatus 



130 



