134 



PROF. G. J. ALLMAN ON LIMNOCODIUM VICTORIA. 



codium differ from those of the Trachomedusse andNarcomedusa3,as 

 well as from Obelia, in their great extensibility, the four primary or 

 perradial tentacles admitting of extension in the form of long, 

 greatly attenuated filaments to several times the height of the ver- 

 tical axis of the umbrella, even when this height is at its maximum, 

 and being again capable of assuming by contraction the form of 

 short thick clubs. Indeed, instead of presenting the comparatively 

 rigid and imperfectly contractile character which prevails among 



rig. 2. 



The Medusa with its tentacles extended, and the umbrella in a medium state 

 of contraction. Magnified about 8 diameters. 



the Trachomedusse and theNarcomedusse, the tentacles of Limno- 

 codium possess as great a power of extension and contraction as 

 may be found in those of many Leptomedusae {Thawmantidce &c). 



