cut off from the body cavities in this stage there 

 still remain traces of the interradial pouch:-.- which 

 ::-.-: rise- tc it .FIG.29.hip 1-2, and 4-5. 



The hypogastric snterdGC-eie itself has changed 

 very little since stage "E" but the epigastric has 

 -has enlarged to such an extent that its edges now 

 meet the edges of the hypogastric and a circular 

 aboral mesentery is formed. Figs. 23-29. cm. 



In the water system considerable growth is to t- 

 noted in the tentacles; the end, and first pair of 

 foot tentacles being capable of protrusion consid- 

 erably beyond the disk. By means of these tentacles 

 the larvae are able to cling tenaciously to the sur- 

 faces or foreign bodies, it requiring a strong jet 

 of water fre:r: & pipet to detach thorn. Special no- 

 tice was taken to be sure that it was the tentacles 

 and not the larval organ whiGh was used so a means 

 or attachment. 



The second pair of tentacles, ( buccal tentacles) 

 have acquired their ectoderm in this stage and pro- 

 trude, like the other tentacles, over the radial nerves 

 into the radial grooves. Fig, 22. and 2G.t2. 



The axial sinus or ampulla is present in "F" 



