MEDUSAE. 25 



distinctly of the type belonging to the Tiaridae. To place Catablema in'ldmii among 

 the Cladonemidse because of the presence of filaments upon the tentacles when all its 

 other characters are distinctly those of the Tiaridae would, in my opinion, be wrong. 



Placed among the Cladonernidae 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 

 Margelidse. 



The genus Zauclea, sometimes called Gemmaria, which is the generic name of its 

 Hydroid, has tentacles provided with cnidophors situated oil very fine thread-like, 

 contractile stalks. These are not at all like the filaments on the tentacles of Ctenaria 

 or Catablema weldoni. The Hydroid Gemmaria belongs to the Syncoryuidse, and 

 there is no reason, so far as I can see, why Zanclea should not be placed among the 

 Codonidae, 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 

 Tiaridae. 



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 Syncorynidse, but its Medusa is 

 not known. 



In the second sub-family, the Deudrouemidae, 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 Margelidse. 



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 Medusae belonging to these two genera. Suckers also occur in certain genera 

 belonging to the Trachomedusse. Eleutheria 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 Eleutheria and Cladonema to justify their being placed in the same 

 family. 



Zancleopsis is a new generic name for Gemmaria dichotoma of Dr. Mayer (1900), 

 and it is evidently an early stage without gonads. 



It seems to me that the characters selected to distinguish the Cladonemidse from 

 the other great families (Codonidae, Tiaridse, and Margelidae) of the Anthornedusse 

 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 



