HYDROIDA. — HALE. 53 



tiuctiou between the specimens and Billard's figure, which shows 

 two such apertures ; close examination of a number of specimens 

 however revealed a few instances in which the single orifice was 

 replaced by two abreast, exactly as Billard shows them. 



The modification of the hydrotheca- at the proximal ends of the 

 hydrocladia, common to many species, is in certain specimens of 

 H. urceolifera, carried further than I have seen it elsewhere. 

 The first hydrotheca presents a smooth even rim with all trace of 

 denticulatiou wanting, except as regards the anterior tooth, 

 which is not at all reduced. The next hydrotheca is less 

 modified, and so on successively, the normal form not being 

 attained till the fourth, or even the fifth hydrotheca. 



I have not seen the gonotheca?, but Billard's figure shows that 

 they are of the obconic truncate form frequent in the genus. 



Later specimens received from the Australian Museum differ 

 somewhat from that described above, and appear to a^ree 

 pretty closely with Lamarck's type. The present form may 

 conveniently be distinguished as car. scandens, from its climbing 

 habit, which apparently is not shared by the larger form. 



The species has not, I believe, been observed hitherto since 

 Lamarck described it from the Indian Ocean in 1810. 



Loc. — Great Australian Bight, on stems of Aglaophenia mega- 

 locarpa and A. billardi,, 40 to 100 fathoms. 



Halicornakia intermedia, sp. HOV. 



(Plate v., fig. 2 ; Plate vii., tig. 4.) 



Hydrocaulus monosiphonic, about 8-10 inches in heio-ht 

 dividing dichotomously once or several times ; branches in 'one 

 plane and facing the same way, divergent at an angle of about 

 7o Q ; hydrocladia alternate or sub-alternate, two on an internode 

 at an angle of about 65°-70°, both series nearly in the same 

 plane ; nodes slightly oblique. 



Hydrotheca? sub-cylindrical, broader near the base, set at an 

 angle of about 60 u and almost facing the front; a strono- 

 intrathecal ridge proceeding from about the middle of the front 

 of the cell obliquely downwards to about its centre, border entire 

 in front or with an indistinct median tooth, and a broad free 

 rounded lobe behind, three teeth on each side, the centre one 

 large and everted, the others more or less tending towards an 

 obsolete condition ; the aperture into the hydrocladium with a 

 few minute denticles on the margin. No septal ridges in the 

 internode. 



