762 SOME NEW AND RARE HYDROIDA IN THE AUSTRALIAN MUSEUM, 



Gonothecae large, obovate, strongly annulated, (10-12 rings), 

 orifice rather wide, infimdibulate, mostly excentric. 



Hab. Bondi Bay. 



This form might with almost equal propriety be assigned either 

 to S. divaricata or to the southern Australian S. Johnstoni (if 

 indeed it be not, as appears likely, one of a series of transition 

 forms uniting the two). In the bushy habit and the compara- 

 tively short internodes it rather resembles 8. Johnstoni, but its 

 hydrothacse are more like those of S. divaricata, being adnate 

 most of their length, and only slightly projecting forward. The 

 peristome often consists of several successive growths. The gono- 

 thecse are a little smaller than those of the type, with closer and 

 more numerous rings ; the aperture is precisely similar. The 

 polypary is much shorter and more bushy than that of the variety 

 sub-dichotoma, but the pinnae or ramuli, as in that form, are given 

 off at irregular intervals, so that the pinnate habit is lost. 



SERTULARELLA LONGITHECA, n.sp. 

 (Plate XVI., figs. 5-6). 



Hydrocaulus slightly branched, divided by oblique joints into 

 internodes which bear one or occasionally two hydrothecae. 

 Hydrothecso adnate from J to J of their length, long, narrow, 

 tubular, smooth, curved outwards, springing from the sides of the 

 hydrocaulus or partly from the front ; aperture not contracted, 

 with three large teeth, one superior and two lateral. 



Gonothecse rather large, without annulations, somewhat widened 

 laterally, with a shoulder at each side of the aperture ; aperture 

 small, tubular, not expanding. 



Hab. Port Denison. 



The only specimen I have seen was 2 \ inches high, and consisted 

 of a monosiphonic stem with live or six simple lateral branches. 

 The hydrothecae are toothed like those of the S. Johnstoni group, but 

 are nearly double as loug in proportion to their diameter, while 



