THE ALGAE OF BEEMDDA. 59 



Collins. Grows practically everywhere in shallow water, varying 

 much in size, texture, outline, etc. Some forms are rounded and 

 entire, wider than broad; some plane, others folded longitudinally; 

 some cuneate and much divided, some consisting of a few linear 

 laciniae from the top of the stipe, the laciniae up to 3 dm. long and 

 less than 1 cm. wide. All pass gradually into each other, so that 

 varietal or form names are useless. 



Halimeda Lamouroux. 



1. All segments except those bearing branches cylindrical. 4. H. Monile. 

 1. Most segments ovoid or flattened, not cylindrical. 2. 



2. Segments distinctly ribbed. 3. H. tridens. 



2. Segments indistinctly or not at all ribbed. 3. 



3. Segments strongly calcified, firm, thick. 2. H. simulans. 



3. Segments lightly calcified, flexible, thin. 1. H. Tuna. 



1. H. Tuna (Ell. & Sol.) Lamouroux, 1812, p. 186; Collins, 1909, 

 p. 400; P. B.-A., No. 1918; Corallina Tuna Ellis & Solander, 1786, 

 p. Ill, PI. XX, fig. e. Kemp; Moseley; Walsingham, Farlow; Howe; 

 Harrington Sound, Jan., Inlet, Dec, Harris Bay, Dec, Hervey; 

 cave, Agar's Island, Aug., Hamilton Harbor, dredged in 5 meters. 

 Dec, Collins. Not uncommon, but less frequent than H. tridens and 

 H. Monile. Our H. Tuna seems all to belong to forma typica Barton, 

 1901, p. 13, PI. I, fig. 1. 



2. H. SIMULANS Howe, 1907, p. 503, PI. XXIX; Collins, 1909, 

 p. 401; P. B.-A., No. 1916. Tucker's Town, Dec, Hervey. Found 

 only in this one locality and in small quantity. Its segments have the 

 outline of those of H. Tuna, but are thicker and more calcified. 



3. H. TBiDENS (Ell. & Sol.) Lamouroux, 1812, p. 186; Harvey, 

 1858, p. 24, PL XLIV. C; Collins, 1909, p. 398; P. B.-A., No. 1917; 

 Corallina tridens EIUs & Solander, 1786, p. 109, PI. 20, fig. a. Rein; 

 Moseley, as H. incrassata; Walsingham, Farlow; many stations, 

 Collins and Hervey, dredged down to 18 meters. Common nearly 

 everywhere and very variable. Of the various varieties and forms to 

 which names have been given, we have 



Forma typica (Barton) ColUns, 1909, p. 398; H. incrassata forma 

 typica Barton, 1901, p. 27, PI. IV, fig. 39. A stout, stony form, with 

 lower joints short, more or less adherent, upper joints three-ribbed 

 or three-lobed. 



Forma tripartita (Barton) Collins, 1909, p. 399; H. incrassata 

 forma tripartita Barton, 1901, p. 27, PI. IV, fig. 43. A more slender 



