187 HYDROIDA. BALE. 



of the colony, so that for each additional branching point a fresh 

 tube is added. While the latest formed tubes do not reach so 

 far down as the next geniculation, the older ones extend further 

 down in proportion to their age, and probably the fasciculation of 

 the lower part of the stem may be entirely due to them. 



Few of the hydrocladia reach more than about one-fifth inch in 

 length, or support more than seven or eight hydrothecje. The 

 latter are unusually large (about '60 mm. in length), and appear 

 noticeably different in form according to the aspect in which 

 they are viewed. In the absence of any denticulation of the 

 border, other than the anterior tooth, they present a character 

 more commonly found in the genus Cladocarpus. The denticles 

 on the margin of the hydropore are generally situated on a small 

 prominent flap of perisarc. 



In an exact front view two faint lines are seen running nearly 

 parallel along the front of the hydiotheca and diverging in out- 

 ward curves towards the border, where they become nearly or 

 quite invisible. These apparently indicate the edges of a longi- 

 tudinal depression, but they are exti-emely slight, so that if the 

 cell lies a little obliquely the nearer one is not apparent, while 

 the other becomes conspicuous throughout. The part of the 

 hydrotheca-wall on which the anterior tooth is situated is 

 distinctly bent inward, the longitudinal furrow becoming at that 

 part wider and deeper, but without any defined boundary. 



The gonangia, which Jaderholm has shown as of a deep 

 cylindrical form, not narrowed at the top, are not present in our 

 specimens. 



Loc. Great Australian Bight, 80-1 '20 fathoms. 



HALICORNARIA TUBTJIJFERA, sp. nor. 

 (Plate xxxvi., fig. 3.) 



Hydrophyton very small, stem slightly fascicled in parts? 

 dividing into sets of three branches at intervals ; side branches 

 divergent on alternate sides, monosiphonic, bearing only 

 sarcothecae on the proximal portions, nodes oblique, often indis- 

 tinct. Hydrocladia short, alternate, one on an internode. 



Hydrotheese tubular, very long and slender, lying along the 

 hydrocladium for about three- fourths of their length, then 

 curving upwards a,nd becoming erect. ; free portion expanding 

 towards the aperture ; no intrathecal ridge nor fold ; a long 

 narrow process projecting from the lower edge of the hydropore, 

 with two or three minute denticles at the end ; border nearlv 

 horizontal, with a rather large median anterior tooth, incurved, 

 and three slight points (or four shallow emarginations) on each 

 side (sometimes obsolete), back entire, free. No septal ridges. 



