PLATE 4 



EXPLANATION OF FIGURES 



Hybocodon prolifer 



36 The hydroid of Hybocodon, drawn from a preserved specimen. X 8. 



37 and 38 The medusae drawn from preserved specimens, in figure 38 the bell 

 is considerably shrunken. The developing secondary medusae buds are shown, 

 and in figure 38 the gonads on the stomach of the main medusa. X 8. 



39 Longitudinal section of entire medusa, slightly diagrammatic, compiled 

 from several sections. Shows stomach with ovary and actinula, radial canals 

 and marginal bulbs, the bulb on the right being the one from which secondary 

 medusae arise. Portion of tentacle included with bulb on right. X 60. 



40 Longitudinal section through the radial canal and tentacle bulb. X 290. 



636 



