792 SOME NEW AND RARE HYDROIDA IN THE AUSTRALIAN MUSEUM, 



one on each intemode, both series borne towards the front. 

 Hydrothecae rather long, set at an angle of about 40", nearly 

 cylindrical in the distal half, and tapeiing downwards to the base; 

 a fold or rudimentary intrathecal ridge near the base on the side 

 next the pinna ; aperture with a sharp pointed median tooth in 

 front, and on each side a short tooth and a broad rounded lobe, 

 the latter uniting with the lateral sarcothecte, back slightly sinuated, 

 adnate. Hydrothecal internode with two transverse folds, one 

 opposite the base of the lateral sarcothecae, the other opposite the 

 rudimentary intrathecal ridge. Mesial sarcotheca about | as long as 

 thehydrotheca, adnate, only slightly projecting, canaliculate. Lateral 

 sarcothecae canaliculate, directed forward and strongly outward, 

 projecting a little beyond the hydrotheca-margin. Cauliue sarco- 

 thecae conical, canaliculate, two on the .stem at the base of each 

 pinna. 



Gonangial pinna with two or three short distinct joints at the 

 ba.se, bearing only sarcothecae. Corbula very long, consisting of 

 nearly 20 pairs of alternate ribs, springing from separate internodes 

 of the rachis as narrow pinnules, but expanding above into broad 

 leaflets, which are attaclied to each other along tiie margins, the 

 lines of union being provided with a series of small canaliculate 

 sarcothecae : a short lateral spur projecting outwards and forwards 

 from the distal side of each rib just above the base, bearing several 

 sarcothecae larger than the rest, but no hydrothecae. One or more 

 of the proximal ribs free, not expanded. A small sarcotheca on 

 the rachis below the origin of each rib. 



Colour, dark brown. 



Hah. — Off Port Jackson. 



The specimens were incomi)lete, the principal one consisting of 

 a fragment of the fascicled stem with two branches about an inch 

 apart on the same side set almost at right angles with the stem, 

 the longer one being complete, and about three inches long. The 

 piece of stem was about ,o inch in diameter, and retained the 

 pinnae almost throughout. The form of the hydrotheca-margin is 

 different from that of any other species known to me, and the 



