150 Ulothricaceae 



to be younger forms of U. zonata. In the two stations above 

 quoted, however, we have never been able to find typical speci- 

 mens of U. zonata. We feel compelled, therefore, to retain this 

 species for the present, although the remark of Hansgirg, that it 

 apparently belongs in the cycle of forms of U. zonata, may be jus- 

 tified by future investigation. 



U. tenuissima differs from typical forms of U. zonata, besides 

 being of a smaller diameter, in its deeper green color, in its gener- 

 ally shorter cells and in its thin cell-wall. Nevertheless, certain 

 young forms of U. zonata show a most perplexing similarity to 

 the form described above. 



3. Ulothrix aequalis Kiitz. Phyc. Germ. 197. 1845 J Spec. 

 Alg. 347. 1849 ; Tab. Phyc. 2 : pi. 89. f. 1. 1852 ; Rabenh. 

 Krypt. Flor. Sachs. 1: 264. 1863. Wolle, F. W. Alg. 134. 

 pi. 118. f. 3 - 5 . 1887. 



Myxonema aequale Rabenh. Deutsch. Krypt. Flor. 2 2 : 99- 



1847- 



Hormiscia aequalis Rabenh. Flor. Eur. Alg. 3: 363. 1868. 



Filaments bright green in color; cells 13-16 /1 in diameter, 

 1-2 times as long. 



In a rapidly flowing brook, attached to stones, Woodlawn, 

 New York, May (57 iB). 



This specimen, when collected, was strikingly different in ap- 

 pearance from U. zonata, but deteriorated speedily. When the 

 station was revisited a few days afterward to obtain material for 

 drawing and further study, all traces of the plant had disappeared. 



A specimen distributed as Hormiscia aequalis Tild. Am. Alg. 

 132, is Microspora sp. 



4. Ulothrix oscillarina Kutz. Phyc. Germ. 197. 1845 I Spec. 



Alg. 346. 1849; Tab. Phyc. 2 : pi 88. f. 1. 1852. Rabenh. 



Flor. Eur. Alg. 3: 366. 1868. Wolle, F. W. Alg. 137. pi. 



1 18. f. 34-36. 1887. (?) 



Conferva oscillator ioides Agardh, Disp. Alg. Suec. 29. 181 2; 

 Syst. Alg. 89. 1824. (?) Not Kiitz. Alg. Dec. 54. 1833 

 ( = Gloeotila oscillarina Kiitz. Phyc. Gen. 245. 1843 = Stigeoclo- 

 nium setigerum Kiitz. Phyc. Germ. 198. 1845). 



Ulothrix oscillatori oides Crouan, Flor. Finist. 122. 1867. (?) 



