294 BULLETIN OF THE 



hfiTig from the incisions between two marginal lappets. The remaining six ten- 

 tacles are of smaller size, and are irregularly placed as regards the incisions 

 between the marginal lobes. The tentacles have a brownish color above, and 

 are white on the under side. The two marginal lobes adjacent the marginal 

 sense bodies are larger and more prominent than the others. In the interval 

 of bell margin between them there are five smaller lobes. Each lobe is leaf- 

 shaped, pointed, and very flexible. In each lobe there ends blindly, without 

 dendritic ramifications, a chymiferous vessel, which is a prolongation from a 

 cavity, or system of vessels in the disk. There are four ovarian openings, each 

 of which lies in a radius drawn from alternate marginal sense bodies. They 

 resemble most closely similar openings in Aurelia. The ovaries themselves 

 have a pink flesh-color. The ovarian filaments are well developed. The mar- 

 ginal sense bodies are highly characteristic. When looked at from the aboral 

 side, in the region of the bell margin in which the otocyst lies, there is in its 

 immediate vicinity a small pit or depression in the bell walls. This pit is 

 identified as a " Riechgriibschen." It is commonly regarded in other medusae 

 as an organ of special sensation. The situation of this pit in Dactylometra is 

 such that one cannot help being reminded that it may be simply the thinning 

 out of the bell walls above the sense body in order to increase the sensitiveness- 

 of the otocyst below. The oral curtains, whicb are so prominent on each side 

 of the otocyst of Cyanea, are wanting in Dactylometra. The two lappets found 

 one on each side of the marginal sense body of Aurelia also fail. Two well- 

 marked inner Riechgriibschen are found one on each side of the base of the 

 style. The ocellus is inconspicuous or wanting. The otocysts do not differ 

 from those of other Discophores, and are formed of a simple sac with enclosed 

 otoliths. They have a whiti-sh straw color, and are easily seen from the aboral 

 side, showing through the bell walls at the bottom of the recess or pit called 

 the outer Riechgriibschen. 



HYDROIDA. 



Calycidion formosum, Fewkes. 



A further consideration of my former* identification of Turritopsis nutricula, 

 McCrady, has convinced me that I was WTong in my determination of this 

 medusa. The jelly-fish which was mistaken for T. nutricula resembles in 

 some respects Podocoryiie, and may perhaps be found to be a new genus and 

 species, for whicb I suggest the name Calycidion formosum. The medusa 

 which was referred in the same paper to Modeeria and described as M. multi- 

 tentacula, sp. nov., is probably the same as T. nutrictda, McCr. As the generic 

 name Modeeria is older tlian Turritopsis, and as they seem to have been applied 

 to similar jelly-fishes, McCrady's medusa may later be known as M. nutricula. 



* Bull. Mas. Conip. Zool., VIII. 7. 



