198 Rev. T. Hincks's Contributions towards a 



the simpler and more primitive form which we have in Beania 

 mirabilis. 



The zooeeium of Stolonella bears a general resemblance to 

 that of Beania ; but there has been an important modifica- 

 tion of one element The spines are converted into flattened 

 ribs, which bend in over the aperture, meeting in a central 

 line, and are united by a membranous or membrano-calcare- 

 ous expansion, so as to form a continuous wall. 



Stolonella clausa, n. sp. (PI. VII. fig. 6.) 



Stolon jointed at regular intervals, opposite branches given 

 off close to each joint, one (usually) rudimentary and bearing a 

 branched disk at its extremity, the other celliferous and itself 

 branched. Zocecia originating close to the lateral branches, 

 jointed to a short process, elongate, erect, boat-shaped, slender 

 as seen in front, and tapering slightly towards the base ; dorsal 

 surface smooth and highly glossy, curved outward below ; on 

 each side of the aperture 11—14 flat and rather broad spinous 

 ribs, which bend in over the opening and meet in the centre, 

 united together laterally, the enlarged bases of the spines 

 forming a kind of pattern running the length of the cell ; on 

 each side of the orifice two stout, erect, pointed spines. 



Loc. Creeping over Fucus } Geraldton, West Australia (Miss 



E. Gore). 



The cells of S. clansa bear a certain amount of superficial 

 resemblance to those of Beania australis. Busk (B. M. Cat. 

 pi. xvi. figs. 1-3). The diagnosis of the latter is useless for 

 identification in such a case, as it merely gives the number of 

 the costse ; but if we are to trust the figure in the 6 Catalogue/ 

 the two forms are undoubtedly distinct. The cells of B. aus- 

 tralis (to take a single point) are represented as attached by 

 the whole of a rather broad base to a decumbent stem ; whereas 

 those of the present species are jointed by the extremity of the 

 dorsal surface, which terminates in a blunt point, to a process 

 from the stolon. The contour of the two below is quite dis- 

 similar. A suberect tubular process is also figured by Busk 

 as rising from the stem near the base of the cell j but nothing 

 of the kind is present in Stolonella clausa. 



The adhesive disks are a very marked characteristic of the 

 present form, and would hardly have escaped the notice of so 

 practised an observer as Mr. Busk. They are commonly 

 bilobed, consisting of two disks joined together. 



Sometimes the branching is luxuriant and the zooecia are 

 rather densely clustered. The lateral offshoots exhibit exactly 

 the same structure as the main lines of stolon, and give off in 

 the same way their branches and disk-bearing processes. 



