1 08 Proceedings of the Royal Society of Victoria. 



soft pfii'ts, I found the circular apertures tli rough wliich the 

 naked sarcostyles had been protruded, and which would scarcely 

 have been noticed without a special search, owing to the tenuity 

 of the perisarc around them, and to the fact that their peculiar 

 position rendered it difficult to get a clear view of them. The 

 perisarc of the liydrocladium curves upward to meet the back of 

 tlie hydrotheca, and the circular aperture is situated in this 

 curved-up portion, nearly vertical to the hydrocladium, so that, 

 whether the latter be viewed laterally or in front, the aperture is 

 turned edgewise to the observer, and is therefore not noticeable, 

 the perisarc being so delicate that the interruption of continuity 

 is only to be seen by careful focussing. However, if a hydro- 

 theca can be found tilted up perpendiculnrly, the orifice is readily 

 distinguished. In K. inirabili<; the hydrotheca is formed on the 

 same model, but the perisarc \i thicker, and the interruption in 

 it can be easily seen in optical section, as I have shown in 

 Figs. 4-5. The sarcostyles, which are present in most of Mr. 

 Wilson's specimens, are not altogether unprotected, as the perisarc 

 is extended into a slight web on each side of the hydrotheca, 

 which it joins to the pinnule, so that the sarcotheca is to a great 

 extent sheltered in every direction except in front. In Jickeli's 

 specimens the cauline sarcostyles were all naked, but in our two 

 species they are usually provided with saroothec^e more or less 

 developed ; I have found them entirely absent, but it is possible 

 that in those cases they had been broken off. 



The gonangia have no distinct marginal ling or operculum, but 

 open by an irregularly circular line of fracture at the summit. 

 Those of K. mirabilis are very large, and free, those of K. pro- 

 ducta are smaller but of similar type, modified however by 

 having one side flattened and adnate to the substance to which 

 the hydrorhiza is attached. 



As hereafter mentioned, the special character on which the 

 genus Diplocheiliis was founded is not really present ; there is 

 therefore no reason why the only species should not be trans- 

 ferred to the present genus, where it rightfully belongs. (See 

 Kirchenpaueria mirabilis.) The genus Azygoplon, Bale, must 

 also be cancelled, as the only species, A. productum, is now 

 proved to be referable to Kirchenpaueria. 



