586 THE AUSTRALIAN HYDROMEDUS.E, 



On the vortex of the Umbrella there is no Gallert pro- 

 truberance. The Polyp colonies are gymnoblastic Hydroids with 

 two verticils of filiform tentacles, the Medusae bud at the base of 

 tentacles belonging to the aboral verticil. 



ISO. EUPHYSA AUSTRALIS. nov. sp. 



The Medusa. 



Plate XXL, fig. 33. 



Umbrella semiovate. Stomach cylindrical, about half as long 

 as the Umbi'ella is high. The developed tentacle long and very 

 retractile with rings of Cnidoblasts in the Ectoderm. 



The other three tentacles quite rudimentary, all equal in size, 

 and not so long as broad. 



The ocellar bulbs are lai'ge and the three smaller ones about 

 half the diameter of the larger. 



Colour : Medusa colourless and transparent. Mouth deep 

 violet. In the Gonad on the Manubrium 4 brown patches and 

 also a few brown spots at the proximal end of the Manubrium. 

 Ocellar bulbs and the large tentacle brown, with violet spots. 



Size ; Height of Umbrella, 2'5 mm. ; breadth, 1*7 mm. (The 

 Umbrella becomes shorter and broader after death, in consequence 

 of the relaxation of the Subumbral muscles.) 



The Polyp colonies and Ontogenesis are unknown. 



Locality : Port Jackson, rare ; caught 3 specimens with the 

 surface net. 



Season : May and June. 



II. SUB-FAMILY. TIARIN.E. 

 TIARID^E. Haeckel. 



Anthoruedusidce with four broad Moutharms, with four or four 

 pair of gonads, four simple Radial Canals and unbranched tentacles. 

 The alimentary Zooids of the Polyp colonies with scattered 

 capitate tentacles. 



