60 COLLIXS AND HEE'\'ET. 



form, less branched, the lower joints longer, the upper joints ending 

 in three cylindrical lobes. 



Forma ghacilis Borgesen, 1913, p. Ill, fig. 89. Joints small, sub- 

 circular in outline, not strongly calcified. 



These forms all pass into each other. Borgesen considers H. Monile 

 and H. simulans also as forms of this species, and it may be that he is 

 right as to the former, but the differences between these two, and the 

 three forms that we consider to belong to H. tridens, are greater than 

 the differences among the latter. Gepp and Borgesen prefer the name 

 H. incrassata to H. tridens; the case for the former is stated by Bor- 

 gesen, 1911, p. 136, that for H. tridens by Howe, 1907, p. 501. 



4. H. MoxiLE (Ell. & Sol.) Lamouroux, 1812, p. 186; Collins, 

 1909, p. 399; P. B.-A., Xo. 1915; H. incrassata forma monilis Barton, 

 1901, p. 27, PI. rV, fig. 40; Corallina monilis Ellis & Solander, 1786, 

 , p. 110, PL XX, fig. c. Inlet, Jan., Oct., Dec, Bailey's Bay, Jan., 

 Walsingham, Xov., Tucker's Town, Dec, Hervey; Hungry Bay, 

 April, Collins. Rather common; the forms recognized by Borgesen 

 both occur here. 



Forma bobusta Borgesen, 1913, p. 113, fig. 90. Densely branched, 

 the upper joints cylindrical, the lower tripartite and sometimes resem- 

 bling the upper joints of H. tridens forma tripartita. 



Forma ctlixdrica Borgesen, 1913, p. 113, fig. 91, Less branched, 

 the joints nearly all cylindrical. 



F.uiiLT BRYOPSIDACEAE. 



Bktopsis Lamouroux. 



1. Ramuli distichous. 2. B. pennata. 



1. Ramuli not distichous. 2. 



2. Main branches virgate, with very slender ranmli. 3. B. Duchassaingii. 



2. Outhne pyramidal, branching of several orders, no sharp distioction 

 between branches and ramuli . 1 . B . hypnoides . 



1. B. hypnoides Lamouxoux, 1809, p. 333; 1809b, p. 135, PI. I, 

 fig. 2, a & b; CoUins, 1909, p. 403. Harrington Sound, Jan., Feb., 

 April, Walsingham, March, Hervey; Kemp, May, as B. pluvwsa, in 

 part; cave by Gravelly Bay, April, Collins. 



Forma pholoxgata J. G. Agardh, 1886, p. 28; P. B.-A., Xo. 1870; 

 B. hypnoides Harvey, 1846-51, PI. CXIX. Harrington Sound, May, 

 Dec, Collins; Old Ferry, April, Hervey. 



2. B. DudLiss-UXGii J. G. Agardh, 1854, p. 107; Collins, 1909, 



