24 EDWARD T. BROWNE. 



on liberation from its Hydroid, either has only four perradial tentacles or eight 

 (four perradial and four interradial) tentacles. The tentacles which appear later 

 develop in pairs and in the order shown by these figures 4, 3, 2, 1, 2, 3, 4. Some 

 of the specimens have the groups of tentacles quite close together, which gives the 

 appearance of the tentacles being uniformly distributed round the margin of the 

 umbrella ; but their position is entirely due to the contraction and shrinkage of 

 the jelly, and this is especially noticeable in the specimens preserved in alcohol. The 

 tentacles are solid, and the endodermal core is in direct contact with the endoderm of 

 the circular canal. The lower side of the basal portion of the tentacles in each group 

 is covered with a layer of ectoderm containing nematocysts. There is no well-marked, 

 conspicuous compound basal bulb common to each group of tentacles, such as occurs 

 in Margelis or Chiarella. The tentacles in a semi-contracted condition show at their 

 distal ends conspicuous circular bands of nematocysts (fig. 3), but these bands seem to 

 disappear when the tentacles are fairly well expanded, and the nematocysts become 

 evenly distributed. There is not the slightest trace of ocelli at the base of the 

 tentacles. 



FAMILY CLADONEMIDvE. 



Prof. Haeckel, in 1879, collected together various genera of Anthomedusse 

 having either tentacles with branches, or tentacles bearing appendages armed with 

 nematocysts, or tentacles provided with stalked cnidophors, and placed them in the 

 family Cladonemidse. The character of the family has remained practically unaltered 

 te> the present day, but the genera have slightly increased in number and have been 

 revised and re-classified by Mr. R. T. Giinther (1903) and by Dr. Ilartlaub (1907), who 

 adopts Mr. Giinther's classification of the genera. 



The Cladonemidse are divided into two sub-families : 



1. Pteronemidse with unbranched tentacles having filaments with nematocysts, 



or tentacles armed with cnidophors. 

 Genera Pteronema, Zanclea, Halocharis, Mnestra, Ctenaria. 



2. Dendronemidse, with branched tentacles ; one branch terminating in a 



sucker or adhesive disc, the other branch or branches provided with 

 batteries of nematocysts. 

 Genera Eleutheria ( Clavatella) Zandeopsis, Cladonema, Dendronema. 



In accordance with the classification at present in vogue for the Anthomedusse, 

 the new Antarctic Medusa which I have described under the name of Catablema 

 weldoni on page 13 should have been described as a new genus of the Cladonemidaj 

 and not placed in the genus Catablema of the Tiaridse. Although this Medusa has 

 tentacles which bear appendages or filaments armed with a terminal battery of 

 nematocysts, I do not consider that it has any connection with the Cladonemidse. 

 The structure of the gonads, the basal bulbs of the tentacles, and the mouth are 



