1060 THE THEORY OF TRANSFOEMATIONS [ch. 



calycles are set unilaterally upon a jointed stem, and small cup-like 

 structures (holding rudimentary polyps) are associated with the 

 large calycles in definite number and position. These small calycuh 



IVWIl/W 



\ 



^ 



I 



ah c 



Fig. 515. a, Campanularia macroscyphus Allm.; b, Gonothyraea hyalina 

 Hincks; c, Clytia Johnstoni Alder. 



are variable in number, but in the great majority of cases they 

 accompany the large calycle in groups of three — two standing by 

 its upper border, and one, which is especially variable in form and 

 magnitude, lying at its base. The stem is liable to flexure and. 



Fig. 516. a, Cladocarpus crenatus F.; &, Aglaophenia plurna X,.; 

 c, A. rhynchocarpa A.; d, A. cornuta K.; e, A. ramulosa K. 



in a high degree, to extension or compression; and these variations 

 extend, often on an exaggerated scale, to the related calycles. As 

 a result we find that we can draw various systems of curved or 

 sinuous coordinates, which express, all but completely, the con- 

 figuration of the various hydroids which we inscribe therein (Fig. 516). 



