766 Proceedings of Royal Society of Edinburgh. [sess. 
Ehrenberg, alternating between tbe large tentacles, were marginal 
clubs, similar to tbe marginal clubs (cordyli) found in Laodice. 
The manner in which Ehrenberg has figured tbe small tentacles 
makes them resemble cordyli in appearance. As Melicertidium 
octocodatum has no marginal clubs or cirri, the sole distinction 
which separates it from the genus Melicertum disappears. 
After due deliberation, I think it would be best to retain and 
amend the genus Melicertidium , and to do away with the genus 
Melicertum. To retain the latter genus would only lead to more 
confusion, as it is clear that Melicerta or Melicertum of Oken is not 
the same genus as Melicertum of Agassiz. It is really a new 
genus, with a new type species. 
I propose the following alteration : — 
Genus Melicertidium, Haeckel, 1879. 
Thaumantkhe, with eight gonads on the course of eight radial 
canals. Numerous tentacles. 
Species. — M. octocostatum (Sars), 1835. (The type species of 
the genus.) 
Distribution. — North Atlantic ; Europe. Northern 
limit; Norway, Bergen. Southern limit; 
England, Falmouth. 
M. campanula (A. Agassiz), 1865 (non Fabricius). 
Distribution. — North Atlantic ; North America. 
Northern limit; Bay of Fundy, Grand Manan. 
Southern limit ; Massachusetts Bay. 
M. georgicum (A. Agassiz), 1862. 
Distribution. — North Pacific ; British Columbia,, 
Gulf of Georgia. 
Note on Melicertum proboscifer, Maas, 1897, p. 19, taf. ii. 
figs. 5-7. 
I do not think that this medusa can be included in the genus 
Melicertidium , as it looks like a Trachomedusa, belonging to the 
genus Agliscra. It was collected on the “ Albatross ” Expedition 
in the Gulf of Panama. 
Maas considered it to be one of the Thaumantidse because he 
did not see any marginal sense-organs. The “ Albatross ” Collection 
was sent to Dr Mass for examination, so that he had only preserved 
specimens to work upon. 
