62 



THE SCYPHOMEDUSAE 



(Tessera), to which eight adradial (Tesserantha) or even more may 

 be added ; or else (2) is divided by incisions into eight hollow 

 adradial lappets ; on each lappet is seated a bunch of capitate 

 tentacles, and between the lappets lie perradial and interradial 

 marginal anchors or colletoci/stophores (Haliclystus, Fig. 3), which 

 are, however, absent in some genera (Lucernaria). The marginal 

 anchors are modified and shortened tentacles, at the base of each 



cc 



Fk;. 2. 



Diagrams illustrating the stnicture of Lucprnaria. 1, longitiulinal section ; the riglit 

 half passes along an adradins, just missing a niesenterj', which is shown in thin outline 

 and carries gastric filaments and generative organs ; the left half passes along an interradius 

 and shows the course of a subunibral pit deeji into the substance of the mesentery. 2, transverse 

 section ; the right half at the level of the stoino<lai'Um, the left half a little below that level, 

 and through thi- ujiper part of the subunibral jiits. 3, transverse section ; the right half through 

 the lower part of the subunibral pits, the left half through the ba.se of the animal where the four 

 niesi-nteries fuse, centrally dividing the coelenteron into four pouches. In all three figures ecto- 

 derm is strongly hatcheil, endoderm lightly hatche<l, niesogloea black. C, coelenteron ; CC, 

 circular canal ; G, genital organ ; GF, gastric lilament ; /, interrmlius ; LM, ectodennal longi- 

 tudinal muscle band, continued aborally into the niesogloea ; M, nicsenterj' ; P, perradius ; HP, 

 subumbral pit ; ST, stomodaeum. 



lies a pad of nematocysts and adhesive cells. No organs of 

 special sense are devcloj)ed in this group. 



The mouth, which is often frilled, leads into a tube, which is 

 probably a stomodacnin, or invagination of ectoderm. At the bottom 

 of the stomodaeum lies the gastric cariiy, which is imperfectly 

 divided into four pernuUal rJiamlxrs, homologous with the perradial 

 canals of Ilydromedusae, by four interradial mesenteries or partitions 



