Australian Hydro ids. \2l 



The specimen now in (juestion has hydii^tliecae about 1 luin. in 

 length, or slightly larger than those of //. para.sifira, and more 

 than double tlie average of //. svaiuhns, and stout in proportion. 

 It agrees perfectly with Von Lendenfeld's figure, except that the rim 

 of the hydrotheca is a trifle less everted. This rim is douliled in one 

 case, but tlie two rims are extremely close together. It is growing 

 on Si/iif/ier/ i/iii a/fer/tdiia. as shown in tlu' tigurt', and for mm- 

 parison 1 ^ivf a figure on tlie same scale of S. ri/Undiicnin witli 

 H. scandtns growing on it. The hydrothecae of the two species of 

 Syntheciuin are of about the same size, and it will be seen that the 

 comparatively gigantic hydrothecae of H. cylindrica surpass in size 

 those of the St/nfliec/iitn as much as the latte)- exceed those of //. 

 scandetis. 



The specimen of S. (dftnuuis on which this //tbelhi was Inuud 

 was a small piece (apparently a pinna) sent to me by Dr. Ki)k- 

 patrick from the " Challenge!- " collection. I at first contemplated 

 describing the HeheUa as new, l)ut on compiuing it with Von Len- 

 denfeld's account of H. cylindrica, found it so closely similar as to 

 suggest the strong probability of their being the same. This con- 

 clusion is arrived at from the figure of the supporting hydroid. as 

 well as from that of the Hehella itself. Von Lendenfeld says tliat 

 the species grows on Sertularians, but mentions no particular 

 species. The figure agrees, however, very fairly with Syntheciuin 

 alfernans, and not Avith any other Sertularian which I am 

 acquainted with; moreover, the relative sizes of the Sertularian and 

 the Hehella are much the same as those of S. alfernans and the 

 species under consideration ; there is every probability therefore 

 that these two ai'e the same foi-ms tliat Von Lendenfeld lias figured. 



The species differs from //. xcnndens (at least so far as this sjieci- 

 men is concerned), in the absence of the chitinous "floor" of the 

 hydrotheca. There is <ui unmistakable " floor," on Avhicli the 

 flattened base of the hydianth is supported, but it appears to l)e 

 purely membranous, and nor an ingrowtli of tht- perisarc, as in 

 H. scandens. 



Sertulakia loculosa Bale. (Plate XII.. Figs. 7. 8.) 



Serfularia loculosa. Bale, Aust. Hydr. Zooph., 1884. p. !)1 



(part), pi. iv., figs. 5, 6, pi. xix.. fig. !) ; Warren, .Ann. 



Natal (iov't. .Mtis.. i.. li)()8. p. :m\. ti<r. 8. pi. xlviii.. fig. 



:57. 

 Serfularia tiirhinafa, Billard, Ann. Sci. Xat., 9 scr.. xi.. 



1910, p. 19 (in part); ( ?^ Ritchie. Proc. Zool. Soc. 



Lond., 1910. p. 821. 



