142 COLLINS AND HERVEY. 



in the same plane; these branches are of 2 or 3 orders, the ultimate 

 about 12 /i diam., the cells about 2 diam. long, nodes more or less 

 constricted; the end cell is distinctly acuminate or subulate. "Dru- 

 senzellen" are abundant, borne usually on the inner side of the lower 

 cell of an ultimate branch, in the same way as a tetrasporangium; they 

 are spherical, about 20 ix diam., or slightly elongate, 18 X 24 /i, with 

 rather thin wall, strongly refringent, yellowish or pale aeruginous 

 contents. Occasionally the cells of a branch or of a system of branches 

 assume a spherical form, as if becoming seirospores, but the contents 

 do not seem to become darker or denser; the end cell rounds the lower 

 end, but remains pointed above. No fructification was observed. 

 The plant is very small, the axis seldom over 1 cm. long, the branches 

 hardly 1 mm.; it is possible that this is not the variety radicans of 

 J. G. Agardh, of which we have not seen type specimens. Descrip- 

 tions as far as we know have been short and imperfect, which has led 

 us to describe the Bermuda plant in rather full detail. 



Crouania J. G. Agardh. 



C. ATTENUATA (Bonnem.) J. G. Agardh, 1842, p. 83; Harvey, 1853, 

 p. 226, PI. XXXI. D; P. B.-A., No. 2048; Batrachospermum attemia- 

 tum Bonnemaison in Agardh, 1824, p. 51, as synonym under Mesogloia 

 attenuata. Very young plants on Caulerpa, Harris Bay, Jan., Nov., 

 plants up to 1 dm. high, washed ashore, Buildings Bay, Feb., March, 

 Hervey. 



Spyridia Harvey. 



1. Branching mostly distichous. 3. S. complanata. 



1. Branching radial. 2. 



2. Recurved prickles at ends of ramuli. 2. S. aculeata. 



2. No recurved prickles. 1. S. filamentosa. 



1. S. filamentosa (Wulf.) Harvey in Hooker, 1833, p. 337; 

 Harvey, 1846-51, PI. XL VI; P. B.-A., No. 1897; Fucus filamentosus 

 Wulfen, 1803, p. 64. Kemp; Tucker's Town, Feb., Harrington 

 Sound, Jan., Feb., Nov., Hervey. Abundant, probably everywhere 

 about the islands. Occasionally handsome plants can be found, but 

 they are mostly matted and unattractive. The three species of 

 Spyridia are much alike in habit; but generally easily distinguished 

 on microscopic examination. 



2. S. aculeata (Schimper) Kutzing, 1843, p. 327; 1862, PI. LI; 



