750 SOME NEW AND RARE HYDROIDA IN THE AUSTRALIAN MUSEUM, 



branch for some distance, and are continued outwards in a bracket- 

 like form, spreading somewhat apart and united by chitinous 

 matter which forms a sort ot web with numerous perforations, so 

 that the outer or lower side of the hydrophore presents the 

 aspect of a number of channels bounded by the ribs, and having 

 perforated or reticulated floors. On the upper side of the hydro- 

 phore further i-eticulations exist. When the polypary with the 

 coenosarc is examined by reflected light the whole mesh of the 

 polypary is seen to be tilled with the whitish coenosarc, with the 

 edges of the superficial fibres everywhere showing as a tine brown 

 reticulation. The hydranths are stout ovate bodies like those of 

 the genus Coryyie, very little narrowed l)elow, and seated directly 

 on the hydrophore. 1 found a difliculty in counting the exact 

 number of tentacles, owing to the specimens being imperfectly pre- 

 served, but there appeared to be usually about eight or ten, four 

 or five of which generally surrounded the oral extremity, while 

 the others were variously scattered over the body, one or two being 

 often found quite close to the base. The capitula are large and 

 globular, with such short stems that they appear almost ses.sile, 

 but this may be caused by the contraction of the tentacles after 

 death. The cceuosarc contains numerous thread-cells, somewhat 

 similar to those of Hydra, but larger. 



The polypary generally attains a height of about three inche.s, 

 and is sometimes slender throughout, and beset with hydrophores 

 for most of its extent, but in other cases the stem and principal 

 branches ai-e very thick and without hydrophores. Doubtless as 

 the oi'ganism increases in growth the older portions become 

 enveloped in fiesh layers of coenosarc, covering the hydrophores 

 and forming a thick trunk as in the ordinary fascicled hydroids. 

 The newly-formed terminal portions of the branches are compressed 

 in a plane at right angles to that of the whole polypary. 



