BY R. VON LENDENFELD, PH.D. 985 



7. Bale enumerates in his catalogue two species of Sertularia 

 under the same name, viz., tridentata, Sertularia tridentata, 

 Lamouroux, (catalogue, p. 96) and Sertularia tridentata, Busk, 

 (catalogue, p. 79.) 



In my former papers I have accepted these two, the Lamouroux 

 species of which seems "doubtful, being not sufficiently described 



I have lately obtained a Hydroid in Port Jackson, which I 

 believe may be identical with Lamouroux species, which I propose 

 to re-name Sertularia tridens, von Lendenfeld. 



Stem slightly branched, irregularly pinnate with very short 

 pinna?. Cellules campanulate, adnate throughout their entire 

 length, cylindrical or wider at the base than at the mouth, 

 parallel to the pinnse, very distinct, alternate. Aperture with two 

 small rounded teeth in front, and one long and sharp spine on the 

 outer margin. Height, one to two centimetres. 



Port Jackson, New South Wales. 



