Australian Hydro ids. Ill) 



disposes sur une rangee." According to the figure the aperture is 

 circular and entire. 



Tin' goiiiuigiuiii i)f //. xra/idens and //. roiitorfa is not recurved 

 idniucopia-fashioii, and its wall is not smooth, hut feehly annu- 

 lati'd ; its apertuic when mature is divided into several shallow 

 enuuginations, each witli its opercular flap. As Levinsen justly 

 remarks, " The gonothecae of //. contorta seem to be very different 

 from tliose of //. calm rat a and H. cj/II ndrica, figured by Agassiz 

 and Pictot." 



As to the gonophores themselves. Pictet says, " Dans cette espece 

 \^H . scatidens] en eft'et. les gonotheques contiendraient deux gono- 

 phores renfermant chacun trois a quatre ceufs et surmontes d'un 

 gros blastostyle en forme de trompette, tandis que sur les exemplaires 

 recoltes a Amhoine. les gonotheques renferrnent trois bourgeons 

 medusoides en forme de cloche tres facilement reconnaissables." 



He goes on to suggest that the apparent blastostyle of H. scandenx 

 is really the first medusoid bud, an erroneous interpretation having 

 been given to badly-preserved specimens. The suggestion as to the 

 blastostyle is somewhat extraordinary, as it is difficult to imagine 

 liow- the structure which I have figured (as it exists) could be con- 

 fused with a gonophore ; nevertheless, I have no doubt that Pictet 

 is correct in supposing that the gonophores are medusoid, and it is 

 quite possible that three may be produced, though not all at one 

 time, as in the form Avhich Pictet has figured. In the few specimens 

 which seemed to be complete there appeared first the large trumpet- 

 shaped blastostyle. then the first gonophore. w'hich, however, was not 

 in a condition to enable its structure to be made out satisfactorily, 

 and l)elow this the second bud, an ovate body in a much more rudi- 

 mentary stage of development. In one or two instances there was 

 at the base of the gonotheca a slight enlargement, which may perhaps 

 have been the earliest rudiment of a third medusoid, but its minute 

 size and the presence in each case of foreign matter obscuring it 

 made its character a matter of uncertainty. If a gonophore, its 

 development must be very late, for even in a case where the first 

 had escaped, and the second seemed mature, it was still apparently 

 no further advanced. 



On the whole I conclude that Pictet 's own account of both the 

 gonotheca and its contents, if correct, furnishes strong evidence 

 against the identity of his specimens with H. scandens, and reasons 

 will be given for believing //. cylindrica to be an entirely different 

 species. I have not seen //. cyU7idrata, and therefore offer no 

 opinion regarding it. As to H. calcnrafa. it may possibly be the 



