392 APPENDIX. 



single series on one side of the rachis, as in S. digitalis, 

 but are widely different in form. 



9. S. operculata, Linn. 



. Hab. — Swan Island, Banks Strait. 



This species occurs in aU parts of the world. It is to be 

 careftdly distinguished from S. bispinosa, Gray, — also an 

 Australian and New Zealand species, but which does not 

 occur in the present collection. 



h. Cells (on the branches) secund, contiguous. 



10. S. diver gens, Lamouroux. 



Cells urceolate, much contracted towards the mouth ; 

 upper half free, divergent, projectiug laterally almost 

 horizontally; mouth small eUiptical, with the long axis 

 looking directly outwards; two lateral teeth. Ovicell 

 smooth, rounded, ovoid ; oral margin not elevated. 



Hab. — Swan Island, Banks Strait. 



Colour hght yellowish : parasitic upon a fucus. Height 

 from 5^ to -g inch; simply piunate, branches distant, 

 regularly alternate. The stem is divided into internodes, 

 from each of which arises a single branch. The cells on 

 the stem are alternate. 



b. Cells secund. 



11. )S. trigonostoma, n. sp. 



Cells ovoid, gibbous, much contracted towards the 

 mouth. Very small portion free, projecting forwards and 

 outwards. Mouth looking outwards and forwards, trian- 

 gular, with a short blunt tooth on the external angle. 

 OviceU— ? 



Hab. — Prince of Wales Channel, Torres Strait, 9 

 fathoms. 



Colour very light yellowish. Polypidom simply pinnate, 

 about two inches high : longest pinnae about half an inch. 

 Cells small adnate, projecting suddenly at top, and much 

 contracted at the mouth. The mouth is of a triangular 

 form, the longest side of the triangle being below. The 

 cells are placed in paii-s, but one is always a little higher 



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