584 THE AUSTRALIAN HYDROMEDUS^, 



Ontogenesis : I have succeeded in obtaining the Medusae from 

 the Syncoryne-Polyps, and also have bred small Polyp-colonies 

 from adult Medusae, which were obtained with the surface-net. 



Locality : Laminarian zone. Port Phillip (I only obtained the 

 Polypes there, but I do not hesitate to designate them as belonging 

 to this species), Port Jackson, Polyps and Medusae. 



Season : Medusae are produced in April and May. 



178. SARSIA MINIMA, nov. sp. 

 The Medusa. 



Plate XXI., fig. 34. 



I did not obtain any adult Medusae, which I might refer to this 

 species with certainty. The young Medusae with only slightly 

 developed Gonade in the Manubium is very small and has a long 

 Manubrium like the northern Sarsiae. It can hereby readily be 

 distinguished from the foregoing species. 



The Umbrella is semi-spherical with large globular Ocellar 

 bulbs and four tentacles with rings of Cnidoblasts. Manubrium 

 long, stomach, slightly spindle-shaped, nearly cylindrical. 



Colour : Entoderm of stomach pale brown. The Medusae other- 

 wise colourless. 



Size : At time of liberation, 1 + 1 mm. 



The Polyps. 



Plate XXI., fig. 35. 



From a creeping not anastomosing Hydrorhiza slightly branched 

 stems arise, with about two or three Hydranths to the stem. The 

 Perisarc which invests Hydrorhiza and Hydrocaulus is irregularly 

 annulated or wavy throughout, and terminates at the proximal 

 end of the Hydranths with transverse circular margin. The 

 Hydranths possess from 8-12 scattered tentacles and are slender, 

 at the time of forming Medusae they become stouter and produce 

 so many medusa-buds that nothing of their bodies remains visible. 



