THE ALGAE OF BERMUDA. 97 



3. A. corymbiferum (Thuret) comb. nov. ; Chantransia corym- 

 bifera Thuret in Le Jolis, 1863, p. 107; Bornet & Thuret, 1876, PI. V, 

 fig. 3; P. B.-A., No. 1880. On Dudresnaya crassa, Salt Kettle, Feb., 

 Spanish Point, March, Buildings Bay, April, Hervey; Shelly Bay, 

 May, Collins. In Europe and California this species occurs on Hel- 

 minthocladia calvadosii; although the latter is common in Bermuda, 

 the Acrochaetium has not been observed on it, but seems to occur 

 generally on the Dudresnaya. Its filaments have some resemblance 

 to those of the host, and the resemblance might puzzle one unfamiliar 

 with both. But usually antheridia or cystocarps can be found. 



4. A. BARBADENSE (Vickers) Borgesen, 1915, p. 45; Chantransia 

 barbadensis, Vickers, 1905, p. 60. On Liagora elongata, Buildings Bay, 

 March, Hervey. This plant resembles A. corymbiferum, but is kept 

 distinct by Bornet, 1904, p. XX, as well as by Miss Vickers, the dis- 

 tinctive characters being the stouter and shorter cells, and the less 

 developed basal portion. We have compared our plant with an 

 authentic specimen from Miss Vickers, also on Liagora elongata, and 

 find them to agree, except that while in the Bermuda plant most of 

 the filaments are composed of cells agreeing in dimensions with Miss 

 Vickers plant and description, in others the dimensions approach 

 those of ^4. corymbiferum. It is possible that future observations 

 may show that the difference is not specific. 



5. A. LEPTONEMA (Rosenv.) Borgesen, 1915, p. 31; Chantransia 

 leptoncma Rosen vinge, 1909, p. 118, figs. 47^48. On Dictyopteris 

 Justii, Gravelly Bay, Aug., Collins. Our smallest species of the 

 genus. 



6. A. SAGRAEANUM Bornet, 1904, p. XXI; P. B.-A., No. 2181; 

 Cladophora Sagraeana Montagne, 1838, p. 459. On Zonaria lobata, 

 Gravelly Bay, Aug., Collins; On Dictyopteris Jitstii, Buildings Bay, 

 July, Hervey. The Buildings Bay plant almost entirely covers the 

 Dictyopteris with a dense coating, the individual plants up to 5 mm. 

 high, main filaments about 12 fj. diam., branches seldom under 7 IJL. 

 These dimensions are greater than those given by Bornet in his 

 description, but as all other characters agree, it must be considered a 

 luxuriant form of this species. Monospores, 18-22 X 8-10 fj, were 

 observed, on unicellular pedicels in a series on the inner side of a 

 branch near the base. On other individuals were observed tetraspores, 

 not before known for the species. They were arranged similarly to the 

 monospores, but were larger and relatively broader, 28-34 X 17-27 /j.. 

 The division is in the form indicated by Rosenvinge, 1909, p. 85, as 

 characteristic of the genus, cruciate with the first division horizontal; 



