770 SOME NEW AND RARE HYDROIDA IN THE AUSTRALIAN MUSEUM, 



often wanting in some of the calyeles. There is a conspicuous 

 oblique joint at the base of the lowest internode of each shoot. 



Mr. Clarke's figure and description* agree with our specimens, 

 except that he represents the teeth of the hydrotheca-margin for 

 the most part above and below the aperture rather than at the 

 sides ; but one or two of his figures approximate to the present 

 form in this respect, and the other details being precisely similar, 

 1 have little doubt that the identification is correct. The gono- 

 thecse were not present in Mr. Clarke's specimens. 



SERTULARIA ELONGATA, Lamx. 



Coogee. A small specimen with some of the cauline intei nodes 

 bearing only a pair of hydrothecse and no pinnae. 



PASYTUEA QUADRIDENTATA, Ellis and Solander. 



(Plate XIV., figs. 6-7). 



Coogee ; Bondi. 



Of these specimens, that from Coogee most resembles the type, 

 but is distinguished by the internodes being less elongated, so that 

 the sets of hydrothecse are close together. The Bondi specimens 

 are peculiar, a considerable proportion of the internodes bearing 

 only a single pair of calyeles each ; indeed some of the shoots are 

 so arranged throughout, and thus differ in no respect from a 

 typical Sertxlaria. The apertures of the calyeles are directed 

 more to the front than in the type, and have blunter teeth, and 

 the hydrothecae generally, when not united in sets, strongly 

 resemble those of some forms of S. australis and S. loculosa; and 

 as in the latter species the joints between the internodes are in 

 some cases simple and inconspicuous, while in others the upper 

 internode is produced downwards to a point, and the lower is 

 similarly produced upward behind it. 



I observed a single gonotheca, which was sub-globular, with 

 about four not very prominent transverse annulations, and a large 

 aperture with an elevated neck and an operculum. 



* Report on the Hydroida collected during the exploration of the Gulf 

 Stream and Gulf of Mexico, by Alexander Agassiz 1877-78. (Bull. Mus. 

 Comp. Zool., Cambridge U.S., Vol. V No. 10) 



