418 THE AUSTRALIAN HYDROMEDUS^, 



SERTULARELLA JOHNSTONI. Gray. 



This species is found in Victoria, New Zealand, Tasmania and 

 South Australia. It has been described by Gray (1), Hutton (2), 

 Coughtrey (3). Allman (4) and Thompson (5). 



SERTULARELLA DIVARICATA. Busk. 



This species is found in Port Stephens and Bass' Straits, and 

 has been described by Busk (6.) 



SERTULARELLA NEGLECTA. Thompson. 



This species is found in Victoria and South Australia, and has 

 been described by Thompson (7.) 



SERTULARELLA RAMOSA. Thompson. 



It is doubtful if this species really belongs to Australia, as 

 Thompson (8) found only a fragment in Bass' Straits, where he 

 thinks it may have got accidentally. I do not exactly know how. 



4. GENUS. PASYTHEA. Lamouroux. 



The stems arising from the Hydrorhiza are simple or branched 

 dichotomously. The Trophosomes are opposite, in pairs, arranged 

 in sets at some distance apart. 



(1.) Gray and Dieffenbach. Travels in New Zealand. 



(2.) Hutton. Transactions of the New Zealand Institute. Vol. V. 



(3.) Coughtrey. Transactions of the New Zealand Institute. Vol. VII. 



(4.) Allman. Journal of the Linnean Society, Zoology. Vol, VII. 



(5.) W. Thompson. Annals and Magazine of Natural History, Feb. 1879, 

 p. 101. 



(<;.) Bush. Voyage in H. M. S. Rattlesnake. Vol. 1., p. 3SS. 



(7.) W. Thompson. Annals and Magazine of Natural History, Feb. 1879, 

 1> KIO. 



(S.) W. Thompson. Annals and Magazine of Natural History, Feb. 1879, 

 p. 102. 



