DIPURENA CONICA. 181 



chymiferous tubes. This is so contrary to what we have thus far found 

 to be uniformly the position of these organs among Tubularian Medusu3, 

 that there is probably some mistake in Forbes's drawiug. 



Dipurena strangulata McCu. 



Dipurena strangulata McCu. Gymnopli. of Charleston Harbor, p. 33, PI. 9, Fig. 1. 

 Dipurena strangulata Aga8S. Cont. Nat. Ilist. U. S., IV. p. 341. 18G2. 



Charleston, S. C. (McCrady). 



Dipurena cervicata McCr. 



Dipurena cervicata McCr. Gymn. Charleston Harbor, p. 34. 

 Dipurena cervicata Agass. Cont. Nat. Hist. U. S. IV. p. 341. 1862. 



Charleston Harbor (McCrady). 



Dipurena conica A. Agass. 



Dipurena conica A. Agass. ; in Agassiz's Cont. Nat. Hist. U. S., IV. p. 341. 1862. 



In the young Medusa the shape of the bell is nearly sugar-loaf (Fig. 

 301) ; the cavity of the bell is formed by a 

 similar cone, with rounded apex ; the disk di- 

 minishes rapidly in thickness towards the cir- 

 cular tube ; the digestive cavity does not ex- 

 tend quite to the level of the veil ; it is divided 

 by a constriction into two unequal cavities, the 

 upper one {u, Fig. 302) being about half the 

 size of the lower one (/, Fig. 302) ; the w^alls of this cavity are thick, 

 tapering gradually towards the actinostome, which is a simple opening, 

 without labial appendages ; the digestive cavity is scarce- pjg 302. 

 ly contractile ; the lour marginal tentacles are short, the 

 sensitive bulb is large, consisting of minute granular cells, 

 the eye-speck being placed in a small button, standing 

 out slightly from the base of the tentacle on the upper 

 side (the abactinal side). (Fig. 303.) The walls of the ten- 

 tacles are thick ; they are made up of large elongated pol\ - 

 gonal cells, giving the tentacles a striated appearance ; the 

 tube running through the tentacles is exceedingly line, 

 expanding slightly towards the extremity, where it joins 

 the cavity of the terminal club ; the large polygonal cells of the tentar 

 cle decrease in size towards the extremity, where there is a crescent- 

 Fig. 301. Young Dipurena conica ; magnified. 

 Fig. 302. Digestive cavity of a young Dipurena conica. u, the upper part ; /, the lower. 



