786 SOME NEW AND RARE HYDROIDA IN THE AUSTRALIAN MUSEUM, 



turgida in the present paper, however, it will be seen that raniules 

 which commence as true hydrocladia like the rest may become 

 transformed beyond the first internode into true branches, with 

 exactly the same structure as the stem. It is therefore an open 

 question whether the same thing does not happen in Aglaophenia, 

 the rachis of the corbula forming a true branch, and the ribs 

 being modified hydrocladia. It may be noted that two of the 

 species of Aglaophenia described in this paper have the gonangial 

 ramulus provided with a series of sarcothecse only below the 

 corbula, like the proximal portions of the ordinary branches in 

 some species. 



Lytocarpus Phillipinus, Kirch. 

 ( = Aglaopltenia urens, Bale (not Kirchenpauer). 



(Plate XXI., tigs. 5-7). 



Hydrocaulus polysiphonic, branched, 7-8 inches in height, the 

 primary branches all directed to one side, curved outward ; branch- 

 lets forming rather a small angle with the main branches ; pinnae 

 close, alternate, one on each internode, both series springing from 

 the front of the stem or branch. Hydrothecte parallel with the 

 pinna in their longer diameter ; basal part constricted on the side 

 next the pinna ; deeply constricted between the aperture and the 

 mesial sai-cotheca, and abruptly recurved, so that the aperture is 

 nearly vertical ; aperture wide, the sides elevated, each forming an 

 angular lobe (sometimes rounded) ; front entire or with a small 

 tooth, back straight or slightly sinuated, free. Hydrothecal inter- 

 nodes with two slight divergent folds or constrictions — one nearly 

 opposite the basal constriction of the hydrotheca, the other at the 

 base of the lateral sarcothecae. Mesial sarcotheca nearly double 

 the height of the hydrotheca, adnate to it nearly as far as the 

 constriction on the upper side, and mainly rising from it ; free part 

 projecting forward, tapering, with distinct terminal and lateral 

 apertures, and an orifice opening into the hydrotheca. Lateral 

 sarcothecse tubular, divergent, adnate to the hydrotheca as far as 

 the margin and rising abo%'e it, inclined at about the same angle as 



