ECTOPLEURA OCHRACEA. 191 



Ectopleura ttirrieula Agass. 



Eclopleura turricula Agass. Cont. Nat. Hist. U. S., IV. p. 343. 1862. 

 Sarsia turricula McCr. Gymn. Charleston Harbor, p. 36, PI. 8, Figs. 6-8. 



Charleston, S. C. (McCrady). 



Ectopleura ochracea A. Agass. 



Ectopleura ochracea A. Agass. ; in Agassiz's Cont. Nat. Hist. U. S., IV. p. 343. 1862. 



The bell is of uniform thickness from the circular tube as far as the 

 base of the digestive cavity ; here the outline tapers gradually towards 

 the abactinal pole (Fig. 320), giving 

 the upper part of the bell a much 

 greater thickness, and a conical shape. 

 Near the base of the digestive cavity 

 there is a very marked constriction ; 

 it then bulges out towards the middle, 

 contracting again towards the actinos- 

 torne, which is simple ; the opening is 

 formed by the abrupt termination of 

 the walls of the digestive cavity ; there 

 are no labial appendages of any sort, 

 except small bunches of lasso-cells. The 

 tentacles are short ; when swimming 

 about they are usually carried tightly 

 curled up near the circular tube. This '' 



species differs from the S. turricula McCr. in having the surface of the 

 tentacles covered irregularly with innumerable lasso-cells ; they are not 

 arranged in bundles, as in the Charleston sjjecies. From each side of 

 the base of the four tentacles there runs to the abactmal pole (Figs. 

 321, 322) a thread of bunches of lasso-cells {I, Fig. 320), like that of 

 Turritopsis. The bunches are large near the actinal extremity, and 

 gradually diminish to the abactinal pole, where there is only one cell, 

 while near the base of the tentacles the bundles are made up of aggre- 

 gations of clusters of lasso-cells, consisting of two or three cells each. 

 An accumulation of bright yellow pigment-cells forms a ring round the 

 point of attachment of the digestive trunk ; the digestive cavity itself 

 is of a delicate rose color, with whitish bunches of lasso-cells at the 

 actinostome, surmounted by a second light yellow ring immediately 

 above it ; the tentacles are of the color of the digestive trunk, but of a 



Fig. 320. Profile of Ectopleura ochracea, magnified. /, thread of lasso-cells extending to ab- 

 actinal pole ; p, pigment-cells at base of tentacles. 



