296 BULLETIN OF THE 



There are four rosy flesh-colored tentacles, which are generally carried 

 closely coiled about the tentacular bulbs. Their length, when extended, is 

 greater than the height of the bell. In older specimens they are sometimes 

 extended at full length when the medusa is in motion. At rest they are car- 

 ried at right angles to the bell walls, or closely coiled about the tentacular 

 bulbs. At intervals along their outer surface the tentacles bear bundles of 

 lasso-cells regularly placed, equally distant from each other. The tentacular 

 bulbs are darkened by orange-colored pigment scattered through their walls, 

 and in many specimens a single black pigment spot -(ocellus) is found on the 

 under side. The figures of the fully grown medusa which I have described 

 are from a more advanced stage than those given by Mr. Agassiz.* 



The above description of this specie's differs in some respects from the 

 original account which we have of this medusa. The arrangement of lasso- 

 cells on the tentacles is similar to that in Sarsia turricula, McCr. J Although 

 in McCrady's description of S. turricula the lines of lasso-cells found on the 

 external bell walls of E. ochracea were not observed, in other particulars the 

 two medusa? are so much alike that they probably belong to the same genus. 

 The rows of lasso-cells were probably overlooked in S. turricula. The refer- 

 ence of S. turricula, McCr. to Syndictyon, A. Ag., made by Haeckel, has little 

 to recommend it J except the arrangement of lasso-cells on the tentacles. We 

 now know that the same or a very similar regularity exists in E. ochracea, 

 and one more reason for separating the two species E. turricula, A. Ag. and 

 E. ochracea, A. Ag. vanishes. The want of meridional lines of lasso-cells on 

 the outer bell walls of E. turricula, A. Ag. is the main feature by which 

 E. ochracea and Sarsia turricula are known to differ.§ 



* North American Acalephre, pp. 191, 192. 



t Gymnoplithalmata of Charleston Harbor. Proc. Eliot Soc. Nat. Hist., 1857. 

 Mr. Agassiz says (loc. cit.) : " This species (ochracea) 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 species." Accord- 

 ing to my observations they are arranged in regular bundles in E. ochracea. 



t For reference of *S'. turricula, McCr. to Syndictyon, A. Ag.,see Haeckel, op. cit. 

 The validity of the genus Syndictyon is denied by Allman. (A Monograph of the 

 Gynmoblastic or Tubularian Hydroids. Ray Soc, 1871, p. 284.) 



§ E. turricula does not seem to be the young of E. ochracea, since in the young 

 of the latter of the same age, as judged by the form of the bell, the lasso-cells of the 

 tentacles are "irregularly arranged" according to Mr. Agassiz, while in S. turricula, 

 McCr. they are thrown into bundles. 



E. ochracea is closely related to E. Dumorlicri, Van Beneden. 



