PLATE XVI. 



DK'HOCCENIA ST0KE81 Milne iMhvar.ls :iik1 Haiiue. 



Fig. 117. — Transverse .section through part of the upper region of a strongly retracted polyp, showing how the iliscal 



tissues may be drawn downward within the polypal cavity, so as to form the so-called mesenterial 



funnels {cf. fig. 95a). (See p. 434.) X 100. 

 Fifi. lis. — Transverse section of the disk invaginateil between twci mesenteries. The section is much lower than 



that from which the former figure was taken. X 100. 

 Fici. 119. — Transverse section through a small separate polyp with four pairs of <'(.implete mesenteries, none of 



which are directives, and four incomjjlete pairs. The septal invaginations are mainly entoctelic. The 



stomoda'al ridges and grooves are well shown. X 100. 

 Fi(i. 120. — Transverse section througb a mesentery with comjilicated mesogheal jilaitiugs for the su]iport of the 



retractor nniscle. X 300. 

 630 



