BY W. M. BALE. 761 



directions. Mr. Whitelegge informs me that the specimens in the 

 Museum are all similarly attached to the same species of sponge ; 

 it is therefore probable that the association is a constant 

 characteristic. 



SERTULARIID^. 



Sertularella divaricata, var. suh-dichotoma, n. var. 



(Plate XVI., figs. 3-4). 



Hydrocaulus about 6 inches in height, straggling, i-amuli 

 similar to the stem, given off irregularly, but in the same plane ; 

 thicker portions of the hydrocaulus sometimes supporting more 

 than one hydrotheca on an internode. Hydrothecse tubular, 

 adnate most of their height, free pai't slightly bent outwards ; 

 aperture with three teeth, the superior somewhat recurved. 



Gonothecse large, obovate, strongly annulated (9-10 rings), 

 orifice very small, infundibulate, mostly excentric. 



Hah. — Port Jackson. 



The trophosome differs from that of the typical aS*. divaricata 

 only in its habit, the ramuli being given off quite irregularly and 

 at long intervals, while those of the type are borne, vvith some 

 exceptions, below every third hydrothecse on each side of the stem. 

 The gonothecse differ from those of the type simply in the small 

 size of the orifice, which is like that commonly found in the Bass' 

 Straits form of S. Johnstoni. 



Sertularella divaricata, var. dubia, n. var. 

 (Plate XVI., tigs. 1-2). 



Hydrocaulus 1-2 inches high, ramuli similar to the stem, given 

 off irregulaily but in the same plane, thicker portions of the 

 hydrocaulus sometimes sup])orting more than one hydrotheca on 

 an internode. Hydrothecce tuliuhu-, adnate most of their height, 

 free part slightly bent outwards, aperture with three teeth, the 

 superior somewhat recurved. 



