CNIDARIA 



151 



Stem arising from its exumbrellar surface, by which it attaches itself 

 temporarily to seaweed. The edge of the bell is divided into eight 

 lobes, on each of which are several short tentacles and the adhesive 



Fig. 127. Longitudinal sections through A, Lucernaria and B, a strobilizing 

 scyphistoma of Chrysaora. In A the section passes through an interradius, on 

 the left on the exact line of the mesentery so as to show the subumbral pit 

 and on the right to one side so as to show the face of the mesentery. In B 

 only the right side of the section passes through an interradius. C, Trans- 

 verse section throngh. Lucernaria along the line XX in A. D, Ephyra larva of 

 Aurelia. can.c. circular canal; ^. gonad; ^./. gastral filament; e.s. exumbrellar 

 stalk; mes. mesentery; ni.L' longitudinal muscle of mesentery; su.p. subum- 

 bral pit; ten.s. tentacle becoming later a tentaculocyst ; I.R. interradius; 

 P.R. perradius; A.R. adradius with first indication of canal. A and C, 

 altered from Bourne; B, after Heric; D, original. 



organs which are called marginal anchors}- There is no velum and 

 tentaculocysts are absent. The manubrium is well developed and the 

 mouth opens into a spacious gastric cavity which is divided by four 

 partitions, the interradial mesenteries ^ into four broad chambers which 

 ^ Absent in Lucernaria. 



