100 Proceedings of the Royal Society of Victoria. 



It is not impossible that H. gracile and H. parvulum may 

 ultimately prove identical, but so far all my specimens of the 

 former have been monosiphonic, while the opposite condition 

 characterises those of H. parvuhun. 



Sertularia unguiculata, Busk. 



A form of this protean species diffei'ing from those which I 

 have hitherto examined in the total absence of the short inter- 

 nodes, which in most varieties occupy the distal portion of the 

 pinnse, and which bear only one pair of hydrothecse each. Tn 

 the present form all the hydrothecse are as a rule closely adnata, 

 and the pinnse have rarely more than one distinct joint in their 

 whole length, and in the majority of cases not even one. 



Port Phillip Bay (Mr. J. B. Wilson). 



Sertularia tuba, Bale. 



These specimens differ from others which T have examined in 

 the possession of a slender stem some four inches or perhaps more 

 in height, which gives off throughout its whole extent numerous 

 pinnate branches about |-inch in length. The stem, though 

 slender in proportion to its length, is thicker and darker than 

 the branches, but bears hydrothecse similarly arranged ; it tends 

 towards a fascicled condition, being strengthened by one or two 

 supplemental tubes, w^hich also give off" hydrothecal ramuli. I at 

 first concluded that this was a distinct variety, but it is quite 

 possible that it may only be a more fully developed stage of the 

 usual form, with which, in minute structure, it entirely agrees. 



Port Phillip Bay (Mr. J. B. Wilson). 



Sertularella. 



In the Challenger Report Professor Allman suppresses the 

 genus Sertularella on the ground that the distinctions relied upon 

 to justify its separation from Sertularia break down on a critical 

 comparison of a large number of species of the two groups. He 

 does not allude, however, to what I have always regarded as the 

 principal characteristic of the genus Sertularella, namely, the 

 fact that each hydrotheca, at least on the smaller branches. 



