I'll THE AUSTRALIAN HYDROMEDUS.E, 



LAOMEDEA MARGIN ATA. Von Lendenfeld. 

 Bale (1) described this Hydroid from Queenscliff and Port- 

 land, without knowledge of the Polypostyles, as Campanularia 



marginata. 



LAOMEDEA RUFA. Von Lendenfeld. 



Bale (2) described this Hydroid, the Polypostyle of which is 

 unknown, from Holborn Island. 



LAOMEDEA UNDULATA. Von Lendenfeld. 



Quoy et Gaimard (3) describe this species from Algse of Port 

 Jackson under the name of Clytia undulata. 



3. GENUS. LAFCEA. Lamouroux. 



The trophosomes on very short stalks, tubular without oper- 

 culum, and regularly disposed on the Hydrophyton. 



The Histological structure of a representative of this genus was 

 studied by Jickeli. (4). 



The Perisarc consists of three layers, only two of which are 

 visible in the Hydrotheca. The threads which connect the inner 

 surface of the perisarc with the Ccenosarc are exceptionally thin 

 and long. Cindoblasts are found exclusively on the tentacles, and 

 the nettle-capsules are all of one kind. 



LAFCEA FRUTICOSA. Sars. 



This species is cosmopolitan. Bale (2) describes one specimen 



from Busk's collection obtained in Bass Straits as belonging to 



this species. 



4. GENUS. HALECIUM. Oken. 



Trophosomes biserial on the ei'ect stems, subsessile ; jointed to 

 a short lateral process of the stem. There is a sexual difference 

 externally visible in the Polypostyles. 



(1.) Bale. Catalogue of the Australian Hydroid Zoophytes, p. 54. 



(2.) Bale. Catalogue of the Australian Hydroid Zoophytes, p. 54. 



(3.) Quoy et Gaimard. Voyage de l'Uranic ite. 



(4.) C. Jickeli. Der Ban der Hydroidpolypen. Morphologisches Jahrbuch. 



-I VIII., Seite 629. 

 (5.) Bale. Catalogue of the Australian Hydroid Zoophytes, p. 64. 



