HTDROTDA. BALK. 51 



hydrothecoe is also peculiar, in being lowest on the anterior side, 

 the obliquity in this type of hydrotheca being usually in the 

 opposite direction. In side view there is visible a small linear 

 mark on the adcauline wall of the hydrotheca Avhich is seen in 

 front view to be caused by a rather thick band crossing the floor 

 of the hydrotheca from side to side, and forming apparently the 

 rudiment of a posterior ridge. 



The gonotheca? are of a thin membranous character, quite 

 colourless, and so delicate that all of them have become more or 

 less shrivelled and distorted in drying. It is evident however, 

 that they are of the same flat-topped type as we find in 

 H. loHylrofiti-i* and H. iirceolifern. 



On one of my specimens a few of the lowest internodes support 

 two hydrocladia each, which are nearly opposite. As I could 

 find no other similar specimens among those which I examined, 

 I conclude that the condition was abnormal. 



Loc. Great Australian Bight, on stems of Acjlaoplienia 

 megalocarpa, 40 to 100 fathoms. 



HALICORNARIA URCEOLIFERA (Lamarrl-), var. SCANDENS, var. nov. 

 (Plate v., fig. 4 ; Plate vii., fig. 5.) 



Plumnlaria urceolifera, Lamarck, Anim. sans Vert., ii., 1816, 

 p. 125. 



Aglaopheni ft nrceoUfera, Kirchenpauer, Abh. Nat. Ver. 

 Hamburg, v., 1872, p. 29. 



Hallcornaria urceolifera, Billard, Ann. Sci. Nat, Zool. (9), 

 v, 1907, p. 324, fig. 1. 



Hydrocaulus monosi phonic (unbranched ?), about five inches 

 in height ; hydrocladia alternate, one or two on an internode, at 

 an angle of about 45, and both series directed towards the front ; 

 nodes transverse. 



Hydrotheca? cup-shaped, deep, set at an angle of about 40, 

 without intrathccal ridge ; border with a small anterior tooth 

 which, along with the part of the hydrotheca-wall immediately 

 below _it, is abruptly bent inward, the first tooth on each side 

 large, erect, a large triangular tooth or lobe near the middle on 



