460 Rev. T. Hincks on the Production of similar Gonosooids 



who has had the opportunity of observing the reproductive 

 zooids of these two species, informs me that one of them has 

 thread-cells on the umbrella, and the other not. He believes 

 that they are present on that of C. cximia ; and this opinion is 

 confirmed by Mr. G. Hodge's drawing (PI. IX. fig. 1). It may 

 perhaps be doubtful whether the zooid of C. Sarsii is always 

 destitute of them. They seem to be represented in Sars's figure 

 of this species (Fauna Litt. Norvegise, tab. 1. figs. 3, 4). But, 

 at any rate, if there be a difference between the gonozooids of 

 these two species, it is of the slightest kind. 



In the case of Stauridia producta and Coryne cximia the iden- 

 tity is complete ; and it is the more remarkable as the polypes 

 are generically distinct. 



The gonophores of the Stauridia are produced at the base of 

 the lower capitate tentacles. I have not observed more than 

 two on a polype ; and of these one was in a much more advanced 

 stage of development than the other. They are pyriform at first, 

 very slightly pedunculate, and of a pinkish colour. The con- 

 tained zooid gradually assumes a hemispherical form as develop- 

 ment proceeds ; the marginal portion of the disk is folded in, 

 and the knotted arms lie in the interior. After a while, the 

 investing sac of the gonophore appears to be ruptured by the 

 frequent contractions of the umbrella, and by the same move- 

 ments the involved portion of the disk bearing the tentacles is 

 slowly forced out. In the case which came under my observa- 

 tion, half the margin, with two tentacles, was first pushed out ; 

 after a few more violent spasms, the other half followed ; and 

 almost immediately the little crystal bell, with its rose-coloured 

 manubrium and four rose-coloured tubercles, from which as 

 many beaded arms were pendent, liberated itself and moved 

 gracefully through the water. (PI. IX. fig. 2.) The umbrella 

 is studded with thread-cells, which show as bright points against 

 a dark ground. From the centre is suspended a rose-coloured 

 manubrium with a simple mouth. Four radiating vessels pass 

 from the base of it to the marginal canal, and are continuous 

 with as many tentacles. The latter originate in four rose- 

 coloured tubercles, on one side of which is placed a dark reddish- 

 brown ocellus*. The arms are very extensile, and are set, along 

 their entire length, with knot-like clusters of thread-cells, and 

 terminate in a large group which forms a spherical bulb at the 

 tip. I have counted about three dozen of these clusters on a 

 single arm. There are no marginal bodies except the tentacles. 



A comparison of this description (which is taken from the 



* Dujardin describes the ocellus of Coryne Sarsii as " black ;" Sars, 

 however, calls it " braun-rothen." The colour in the Stauridia is so deep 

 that it might readily be mistaken for black. 



