by Zanardini on an Alga of the Adriatic. It is interesting to find, 

 at such opposite geographical points, closely allied Algse of such 

 remarkable organization. 



A. Ti°\ 1. Halodictyon arachnoideum, — the natural size. 2. A portion of 

 the network, magnified. 3. One of the meshes, more highly magnified. 



Plate XXXVII. B. 



HALODICTYON ROBUSTUM, Hon,. 



Halodictyon robustum ; network (scarcely mature) compressed ; filaments 

 setaceous, the primary articulations ovoid, much contracted at the 

 joints, 2-3 times longer than broad ; stichidia ovate-oblong, with 

 beaded margins ; tetraspores biseriate. 



H. rohustum ; reticulo fvix evoluio) compresso ; filis setaceis, articulis ovoideis ad 

 genicula valde contractu diametro 2-S-plo longioribus ; stichidiis ovato-oblon- 

 gis marginatis ; tetrasporis biseriatis. 



Hanowia robusta, Harv. in Trans. R. I. Acad. v. 22. p. 558; Alg. Austr. 

 Exsic. n. 117. 



Hab. Dredged off Fremantle, W. Australia, W. H. R. t G. Clifton. 



Geogr. Distr. As above. 



Descr. The few specimens yet seen are obviously immature, though one or two 

 are in fruit. In the stage observed, the network forms an irregular sponge- 

 like mass, bristling with small hair-like ramuli, and showing indications 

 of erect branches, which probably (in full-grown specimens) become re- 

 peatedly forked. The filaments are as thick as horsehair, composed of oblong- 

 oval cells, containing deep-red endochrome, surrounded by a wide hyaline 

 limbus. The articulations vaiy in length, but are rarely more than thrice 

 their diameter. The stichidia (discovered by Mr. Clifton) are often in 

 pairs, and either issue from the angles of the network or from a free ra- 

 inulus ; they are bordered with a row of inflated, pellucid cells, that look 

 like beads, and contain dark-red tetraspores in a double row. 



This species obviously differs from the foregoing in the shape 

 and dimensions of the component cells. The figures are drawn 

 to the same scale. 



B. Fig. 1. Halodictyon robustum, — the natural size. 2. One of the meshes. 

 3. A pair of stichidia. 4. A tetraspore : — the latter figures more or less 

 magnified. 



