Further Notes on Australian Hydroids. 115 



The perisarc is ordinarily thin, but in some of the shoots 

 the walls of the hydrotheca? are much thickened. The male 

 and female gonangia were on different shoots ; the former 

 seemed rather larger in proportion than those of P. campanula, 

 otherwise there was no important difference. 



Plu.mularia filicaulis, Pffippig. 



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



The specimens consisted of pinnate and undivided shoots 

 growing abundantly from the same hydrorhiza. 



Plumularia procumbens, Spencer. 



(Plate v., figs. 11-12.) 



(Trans. Eoyal Soc. Vic, Vol. II., Part I.) 



Since I received the specimens from Mr. Wilson, Professor 

 Spencer has very fully described and illustrated this species (also 

 from specimens collected by Mr. Wilson) ; I may however add that 

 in a few instances I have found sarcothecte on the short internodes 

 of the hydrocladia, which ordinarily bear no appendages of any 

 kind. The hydrothecje are very small, and in proportion to them 

 the sarcothecse are unusually large. 



Plumularia compressa, Bale, var. 



A form differing from the type only in the size, which does not 

 exceed about |^-inch in height, with all the parts small in propor- 

 tion. Dongarra Beach, Western Australia (Mr. A. J. Campbell). 

 A similar variety occurs in Port Jackson. 



Plumularia flexuosa, n. sp. 



(Plate v., figs. 6-10). 



Hydrocaulus monosiphonic, unbranched, about one-eighth of an 

 inch in height, stem very slender, flexuous ; pinnae alternate, each 

 borne towards the upper part of an internode and supporting a 

 single hydrotheca, distal part curving abruptly from under the 

 hydrotheca, widening upwards, generally with a constriction 



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