MEDUSA. 25 
distinctly of the type belonging to the Tiaride. To place Catablema weldoni among 
the Cladonemidee because of the presence of filaments upon the tentacles when all its 
other characters are distinctly those of the Tiaride would, in my opinion, be wrong. 
Placed among the Cladonemide is the remarkable Ctenaria ctenophora of Haeckel. 
It has filaments upon the tentacles somewhat similar to those of Catablema weldoni; 
but it has an important character, namely, the presence of oral tentacles round the 
mouth, a character which alone should be sufficient to place it in the family 
Margelidee. , 
The genus Zanclea, sometimes called Gemmaria, which is the generic name of its 
Hydroid, has tentacles provided with cnidophors situated on very fine thread-like, 
contractile stalks. These are not at all like the filaments on the tentacles of Ctenaria 
or Catablema weldont. The Hydroid Gemmaria belongs to the Syncorynide, and 
there is no reason, so far as I can see, why Zanclea should not be placed among the 
Codonide, not far away from the genus Sarsia, which is connected with the Hydroid 
Syncoryne. 
Pteronema is one of Prof. Haeckel’s genera and its two species have not been 
recorded since they were first described. Pteronema darwini has radial canals with 
short diverticula, like those of a Catablema, so it may turn out to be one of the 
Tiaride. 
Mnestra is a curious parasitic Medusa. As the cnidophors on the tentacles are 
much like those of Zanclea, it may belong to the same family. 
Halocharis is a Hydroid genus belonging to the Syncorynide, but its Medusa is 
not known. 
In the second sub-family, the Dendronemide, there are three important genera :— 
Eleutheria, Cladonema and Dendronema. Both Cladonema and Dendronema have oral 
tentacles round the mouth, a character also belonging to the Margelide. 
Eleutheria, better known under the name of Clavatella, is usually associated with 
Cladonema on account of both having suckers on the tentacles. The suckers are 
specialized organs which have arisen and been perfected by a change in the habits of 
the Medusze belonging to these two genera. Suckers also occur in certain genera 
belonging to the Trachomeduse. lewtheria is distinctly a crawling Medusa, and its 
habits are not like those of Cladonema, which is an active swimmer, and only uses its 
suckers for attachment. Except for the presence of suckers, there is nothing in 
common between LEleutheria and Cladonema to justify their being placed in the same 
family. 
Zancleopsis is anew generic name for Gemmaria dichotoma of Dy. Mayer (1900), 
and it is evidently an early stage without gonads. 
It seems to me that the characters selected to distinguish the Cladonemide from 
the other great families (Codonide, Tiaride, and Margelide) of the Anthomedusz 
are more suitable for generic or specific characters, as they are based upon the structure 
of the tentacles. Moreover, the structure of the tentacles does not belong to one 
