6 
90~ 
Ode 
from these ampullae to the tube-feet, along the plate of the ambitus to 
or past the central point of the interradial area (fig. I, 6 and 7), al- 
Fig. III. Inner surface of oral skeleton. 
though I never determined a junction with the system of the next 
radial area. 
Further the ampullae were clearly seen over the whole area of the 
ge 
I 3b 
=> ; 
Fig. IV. Ampullae in various stages. 
1 
irregular skeletal supports which lie between the interradial parallel 
ones, but it was impossible to follow the canals as may be understood 
by examining fig. III. 
Fig. V. Echinarachnius parma. (Aboral and oral surfaces.) 
This proves the presence of an interesting condition which may 
be of considerable value in the comparative study of the different clas- 
ses of Echinoderms. 
