BY R. VON LEXDENFELD, PH.D. 407 



This Sertularia grows in dense bushy tufts, which reach a height 

 of 4 cm. The stems bear few and irregularly disposed branches. 

 The Hydrothecse are alternate, or opposite. Most of them appear 

 to be opposite, but sometimes one is found on one side without a 

 corresponding one on the other (compare the figure.) 



The Gonothecse are very large, and only met with in the 

 proximal portions of the- colony. 



The Hydrothecse bear a larger extei-nal and smaller forward 

 tooth, the back margin is perfectly smooth, the opening lies 

 forward. The Hyclrothecre are adnate their whole length. 



The Gonophor is flat pear-shaped and possesses a large circular 

 terminal opening. 



I found this Hydroid on the i - oots of Microcystis in Port 

 Phillip. It bears Gonophores in September. 



SERTULARIA OPERCULATA. Linne. 



This cosmopolitan species has been found at several places on 

 the coasts of Australia and New Zealand. (1.) It was first 

 described from Australasia by Kirchenpauer under the name 

 Dynema fasciculata (2), and is one of the most common Hydroids 

 of our coast. 



SERTULARIA BISPINOSA, Coughtrey. 



This species has been described from South Australia and New 

 Zealand by Gray (3) and Coughtrey (4). The Sertularia oper- 

 culata of Thompson (5), is, according to Bale (6), probably the 

 same species. I have found this Sertularia on Bryozoa, and also 

 on the roots of Algee in Western Port and Port Phillip. 



(1.) W. Bale. Catalogue of the Australian Hydroid Zoophytes, p. 68. 



(2.) Kirchenpauer. Neue Sertulariden. Verhandlungen der K.L.C.D. 

 Akademie. Band XXXI. , Seite 12, 1S64. 



(3.) Gray. Dieffenbach : Travels in New Zealand, Vol. II. 



(4.) Coughtrey. New Zealand Hydroids. Trans. N. Z. Institute, 

 Vol. VII. 



(5) IF. Thompson. Annals and Magazine of Natural History, February 

 1S79, p. 107. 



(6. ) W. Bale. Catalogue of the Australian Hydroid Zoophytes, p. 68. 

 27 



