the really slender hranches of the frond, invested in this loose fibrous sheath, 

 appear to treble their proper diameter. The true ramelli are simply pinnate, 

 but often have but a sin<;le j)air of junnaj, or even but a single pinna, or 

 are quite naked : their apices are always blunt, and their arlicuhitions 3-4 

 times longer than broad. The endochrowa completely fills the cell, leaving 

 a very narrow, membranous (not gelatinous) cell-wall. No fruit has yet 

 been seen. The colour is a dull red, becoming brownish in drying. The 

 substance is tough and rigid, and (except when very young) the frond very 

 imperfectly adheres to paper in drying. 



This interesting species of Wrangelia is dedicated to Mr. 

 Henry Watts, of Warnamboul, to whom I am indebted for seve- 

 ral packets of the Algae of that part of the Victorian seacoast, 

 including many rare and interesting kinds, and some novelties, 

 among which this is the most remarkable. It is nearly allied to 

 W. crassa, with which it agrees in many points of ramification, 

 but from which it greatly differs in substance and in the micro- 

 scopic appearance of the articulations : in W. crassa each articu- 

 lation has a very narrow endochrome, set in a very wide margin 

 or gelatinous cell-wall ; in W. Wattsii the endochrome fills up the 

 whole space, and the cell-wall is membranous and very narrow 

 or thin. Whatever afiinity therefore there may be between these 

 species, a single cell of either may be readily distinguished under 

 the microscope. 



No fruit has yet been observed on W. Wattsii, but its genus 

 nevertheless can hardly be considered as doubtful. 



Eig. 1. Wrangelia Wattsii, — the natural size. 3. A pinnated raraulus or 

 plumule. 3. Fragment of an old branch, with whorled rarauli and deflexed 

 radicular filaments. 4. Section of a branch : — magnified. 



