42 CXELENTERATA AND 



a knitting-needle; float small. Nectocalyces arranged in 

 two opposite rows on the third of the axis below the float, 

 called the nectostem. Covering-scales flat, quadrangular 

 in shape. Stomachs or polypites, arranged at intervals on 

 lower two-thirds of the axis called polypstem. Tentacles 

 long, contractile, dotted with lateral appendages (tentac- 

 ular knobs). Each tentacular knob with pedicel ; coiled 

 cork-screw part (sacculus) covered by an involucrum ; 

 two terminal filaments and spherical vesicle. Ova and 

 spermatozoa on the same individual or colony. 



A. elegans. 



Nanomia. Body tubular with colored axis ; float small. 

 Nectocalyces arranged in two rows on the third of axis. 

 Covering-scales flat, quadrangular. Stomachs or poly- 

 pites, on two-thirds the axis. Tentacles long, contractile, 

 when retracted thrown into festoons. Tentacular knobs 

 with sacculus, involucrum and single terminal filament. 

 Ova and spermatozoa in respective bells on same colon} 7 . 



N. car a. 

 A. II. 



Physalia. Body bag-shaped, floating on the surface of 

 the water, with appendages hanging down in the water on 

 the lower side. Float pointed at one end with raised 

 chambered crest on the upper side. Tentacles very long, 

 contractile, armed at intervals with reniform thickenings 

 of lasso-cells. Polypites numerous. Sexual bodies in 

 the form of buds on a branching axis. 



P. Arethusa. 



Diphyes. Two small gelatinous nectocalyces placed end 

 to end with openings into cavities pointing in same direc- 

 tion. Anterior conical, with four radial tubes of unequal 

 length and single blind tube called the somatocyst in the 

 bell walls on one side. Posterior bell with radial tubes 

 of the same length, no somatocyst. Axis long, flexible, 



