270 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. 



began to develop on the stomach and also to extend for a 

 short distance along the radial canals. Wright obtained 

 young medusae from his colonies in the spring and 

 autumn. 



-Distribution. — Belgium, Heligoland, Shetland, Cro- 

 marty Firth, St. Andrews, Firth of Forth, Plymouth, 

 Bute, Ballycastle Bay, Dalkey, Kingstown. 



Margellium octopunctatum, (Sars 15). 

 Cytceis octopunctata, Sars {19). 

 Lizzia octopunctata, Forbes (9). 

 Bathhea octopunctata, Haeckel (15). 



Sars first discovered this medusa on the Norwegian 

 coast, and described the species with three tentacles in 

 each of the perradial and interradial groups, and with 

 medusa-buds upon the manubrium. The young medusae 

 on leaving their parent have 3 tentacles in each perradial 

 group and four single interradial tentacles. 



Forbes first added the species to the list of British 

 Medusae and captured the specimens off the Shetland 

 Isles. He observed that all his specimens had three 

 tentacles in each perradial group and either two or three 

 tentacles in the interradial groups. Forbes considered 

 his specimens to belong to the same species as those 

 described by Sars. Haeckel has divided the specimens 

 taken by Sars and Forbes into two different genera, on 

 account of some of Forbes' s specimens having only two 

 tentacles in each interradial group. Medusae with an equal 

 number of tentacles in the perradial and interradial groups 

 belong to the genus Bathhea and under B. octopunctata 

 Haeckel places Cytceis octopunctata, Sars. Medusae with 

 more perradial than interradial tentacles belong to the 

 genus Margellium, and as some of Forbes' s specimens 

 have only two tentacles in the interradial groups Haeckel 



