L.M.B.C. MEDUSA. 273 



The Port Erin specimens with 5 perradial and 3 inter- 

 radial tentacles in each group, are very much like the 

 American species except that the oral tentacles have fewer 

 groups of nematocysts. The other groups of nematocysts 

 may have yet to appear, if so, there will be no reason for 

 separating the English and American species. It is best 

 however, for the present, to keep them apart until more 

 is known about the English species. On my arrival at 

 the Plymouth Laboratory in September, 1893, I found 

 that Mr. Garstang had also been collecting specimens of 

 Lizzia octopunctata , Forbes, during March and April in 

 the Sound. He believes that Bathhea octopunctata and 

 Margellium octopunctatum are the same species, and has 

 recently published his notes (11) which show the develop- 

 ment of the marginal tentacles. In the museum of the 

 Marine Biological Association at Plymouth there are 

 two dozen specimens of Margellium octopunctatum col- 

 lected by Mr. Garstang, all the specimens, except two, 

 have 3 tentacles in all the groups. The two exceptions 

 have their tentacles arranged thus : 



Perradial 3333 3222. 

 Interradial 2323 3111. 



As none of Garstang' s specimens have more than three 

 tentacles in each group, he regards M. octopunctatum as 

 an early stage of Bathhea octopunctata, and the former 

 name is done away with. But the specimens taken at 

 Port Erin show that a further increase does take place in 

 the perradial tentacles, and that there are more perradial 

 tentacles than interradial, which is the characteristic 

 feature of the genus Margellium. Therefore I retain the 

 name of the genus Margellium. 



On Feb. 24th, 1894, I received from Mr. Garstang 

 seven specimens, alive, of the early stages of Margellium 



