sions in the peristome of the earlier stages hr.ve become nearly 

 flattened out, all that remains of them being' the hollows be- 

 tween the projecting angles, or pillars of the proboscis, that 

 are now very prominent. The specimen from which Fig. 40 was 

 taken shows a slight cavity (s. f.) in the pei-istome at the 

 point where each septal muscle joins the general ectodenn. 

 This is E little more marked in Fig. 49 and it is seen at its 

 maximum development in Fig. 50 which is taken from a specimen 

 in which the absorption of the tentacles is nearly complete. 

 It is a funnel-shaped depression into the septal muscle and is 

 a vestige of the septal funnel, which, accordii^g to Goette, is 

 found well aeve loped in Aurelia. 



With the increase in width of the peripheral [portion of 

 Lhe upper disk of ^he strobila, the orifices in the septa be- 

 come relatively larger, until the septa are reduced to colum- 

 nar pillars (c. Fig. 50) of supporting substance that connect 

 the jelly of the peristome or subumbrella with the aboral disk 

 of jelly, or exumbrella. Tliey are clothed with entoderm, or 

 perhaps partially with ectoderm, ancl are pierced longitudinally, 

 each, by a septal muscle. We may speak of these structures 

 now as columellae. 



They are what the Germans call "Septalknoten. " There is 

 of course no adhesion of the two entodermal plates at these 



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