784 SOME NEW AND RARE HYDRO1DA IN THE AUSTRALIAN MUSEUM, 



point, which only rises about as high as the rim of the hydrotheca, 

 instead of being produced into a longer spine. The hydrothecae 

 also are proportionately longer from back to front. 



B ndi Ba PLUMULARIA PULCHELLA, Bale. 



A few fragments of this species occurred along with specimens 

 of Pasythea quadridentata, from the above locality. 



PLUMULARIA COMPRESSA, Bale. 

 Botany. (Plate XIX., fig. 14). 



Except that the base of the hydrotheca is sometimes a little less 

 angular, these specimens agree with the type in all but size, being 

 only about J of an inch high, with all the parts small in propor- 

 tion. The gonosome was wanting. 



PLUMULARIA AURITA, n.sp. 



(Plate XIX., figs. 15-19). 



Hydrocaulus monosiphonic, unbranched, about | inch in height ; 

 stem slender, pinnae alternate, each borne near the summit of an 

 internode, and supporting a single hydrotheca ; distal part curved 

 from under the base of the hydrotheca, smooth, swollen at the 

 summit on the inner side. Hydrothecae rounded at the base, 

 slightly compressed laterally, aperture at right angles to the cell 

 and pinna, margin sinuated behind down to the summit of the 

 pinna, no intrathecal ridge. Sarcothecae monothalamic, or with a 

 rudimentary division, canaliculate, stout at the bases, one below 

 each hydrotheca, fixed, its oblique aperture almost appressed to the 

 front of the cell, one at each side above the hydrotheca, very 

 large, open on one side nearly down to the base, one in each axil, 

 simple, bract-like. 



Gonothecae from 3 to 4 times the length of the hydrotheca, very 

 ^convex behind, nearly straight in front, aperture looking outwards 



