'are entirely due'to muscular contraction but neither do they 

 correspona with the septal funnels found in Aurelia. 



The four gastric pouches are noiv much deeper than in the 

 earlier stages and are in conimunication by means of a small 

 perforation in each septum, close to the base of the interra- 

 dial tentacle (c. s.. Fig. 47). These perforations, together 

 with the peripheral part of the gastric pouches, form the "Ring- 

 sinus" of Clerman authors. There is a slight extension of the 

 cavity of the "Ringsinus" into the btise of each tentacle. Figs. 

 38 and 39. Beyond this the tentacle is solid and has the 

 same stinicture as in earlier stages. The tentacles may in 

 this, as in earlier stages, be divided into two series accord- 

 ing to the position in which they are normally held, the one 

 series being kept more erect, than the other that is nearer the 

 longitudinal axis of the larva. The two series are equal in 

 number and their members alternate. Pig5. 11 ana 13, or 14. 



The differentiation of the epithelium lining of the prob- 

 oscis from the general entoderm is even more marked thsjn before. 

 The two grade into one another on the roofs of the gastric pou- 

 ches, but on the septa the transition is quite abrupt. Fig. 48. 

 There is a slight prominence (g. f.) projectir^g from the mar- 

 |gin of the septum into the stomach. This is covered by a con- 

 tinuation of the lining of the proboscis and in the angle on 



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