BY W. M. BALE. 789 



The thread-cells (which I found in all the specimens) are 

 slender-lanceolate bodies, often slightly curved and reaching an 

 unusual size (about 3-1000 of an inch). The sheath, or axial body, 

 is a very hyaline structure, with markings resembling a loosely- 

 coiled double spiral; the dart is an exceedingly fine simple filament 

 1-100 of an inch, or even more, in length. They are found in 

 profusion, not only in the sarcothecse, but within the cavity of the 

 hydrocaulus, where it seems impossible that they should be of any 

 value as weapons of offence or defence. 



Besides the two sarcothecse on the stem at the base of each 

 pinna, there is one on the basal part of the pinna itself, a feature 

 which I have not observed in any other species. 



The ultimate branches (which are often monosiphonic through- 

 out or in part) have a long oblique joint near the base, between 

 which joint and the origin of the branch there is a series of median 

 sarcothecse, but no pinnse. 



Lytocarpus urens, Kirch., sp. 



(Aglaophenia urens, K.) 



While the specimens which I described and figured in the 

 "Catalogue" under the name of Aglaophenia urens, K., appear to 

 belong to Afflaophenia (Lytocarpus) PhilUpina, K., it is probable 

 that the description there given will apply in most particulars to 

 the true A. urens. Kirchenpauer, however, represents the hydro- 

 theca of that species with the margin entire, or, in Australian 

 sjjecimens, with a small anterior tooth, but without angular lobes 

 at the sides. I am not aware whether L. urens has a sarcotheca 

 on the basal part of each pinna, like L. Phillipinus. 



According to Kirchenpauer's figure and description there is a 

 polysiphonic stem 7-8 inches high, with branches which are mostly 

 divergent almost at right angles, and some of which are rebranched. 

 The stem is blackish, the branches lighter, and the pinnaj are very 

 short. The hydrotheca^ and sarcothecai are of the same general 

 type as those of L. Phillipinus, except in the absence of the angular 



