HYDROIDA. — BALE. 45 



find very little difference, except in regard to the sarcothecae. In 

 A. dannevigi the line of union of two leaflets in the middle of the 

 corbula generally bears about three, in A. macroearpa there are 

 five or six in the corresponding position, the sarcothecae beino- 

 smaller and closer together. In the latter species they are 

 usually widest in the middle, with the aperture small and 

 circular, but having a deep narrow lateral sinuation ; in the 

 former they are cup-like, expanding up to the aperture, which is 

 very wide and oblique, with the margin smooth or somewhat 

 irregular. These distinctions are very definite in the specimens 

 before me, but whether they are constant is hardly a matter of 

 certainty while so few examples of A. macroearpa are available. 



The female corbulae were in many cases crowded with 

 gonophores, but the male were empty. They evidently open by 

 the splitting of the upper side along the median line, and in the 

 narrower distal portion. 



In all the foregoing species the corbulae, like the branches, 

 originate in two successive internodes of the rachis, taking the 

 place which would otherwise be occupied by two hydrocladia. 

 They also follow the same rule as the branches in regard to the 

 direction in which they face. Thus in A. billardi and 

 A. tasmanica the corbula faces mainly forward, like the 

 branches, which all front in the same direction; while in 

 A. dannevigi and A. macroearpa, where the branches have 

 their anterior aspect turned towards the rachis from which they 

 spring, the corbulae have a corresponding direction. When 

 therefore a fertile specimen is laid on a slide with the hydrocladia 

 facing upward, the corbulae will, unless twisted from their normal 

 position, face downward towards the slide. 



Loc.- -Great Australian Bight, 40 to 100 fathoms. 



Aglaophenia megalocarpa, sp. nov. 



(Plate iv., fig. I ; Plate vi., fig. 5.) 



Hydrophyton polysiphonic, two feet or more in height, with 

 numerous branches, mostly on the upper half ; branches alternate 

 or irregular, forming an angle with the stem of about 45-50° ; 

 each branch springing from an internode of the primary jointed 

 stem, opposite to a hydrocladium. Hydrocladia alternate, one on 

 each mternode, both series directed slightly towards the front 

 and rising at an angle of about 40° ; nodes slightly oblique. 



Hydrothecae appearing doubled on themselves, being divided 

 by a strong intrathecal ridge which starts from the back angle 

 of the lateral sarcothecae and proceeds backwards parallel with 



