COSMAEIUM. 15 



species, and in this we are supported by the opinion of Dr. 

 Nordstedt. Hoy and Bissett record the plant as very rare in 

 Scotland, but we are only able to g'ive an incomplete descrip- 

 tion of it and a copy of Nageli's figures. 



Kirchner has described the zygospore of what he considered 

 to be C.Ncigeliannin (Consult ( Kirchn. Xachtrage zur Algenfl. 

 Wiirttemb/ Wiirtt. Naturwiss. Jahr. 44, 1888, p. 154). He 

 describes it as globose, with short processes each furnished 

 with two or three short spines, at the same time remarking 

 that it is like that of C. crenatuui Ralf's. This description 

 also fits the zygospore of G.notdbile Breb. It is very probable 

 that (7. Ncigelianum is only a form of C. notabile. 



Maskell has figured the zygospore of a New Zealand variety 

 of it (var. latum Mask.), which is globose and covered with 

 short simple spines (vide Mask. ' Further Notes N. Zeal. 

 Desm/ 1889, p. 17, t. 3, f. 27). Whatever Maskell's New 

 Zealand plant may be, it is certainly not referable to the 

 same species as " Euastrum (Cosmarium) a-enatum Nag." 



\\Q have for some time past regarded C. orthogonum Delp. 

 as merely a variety of C. Nagelicunum Breb., and this may 

 prove to be the case, but as Delponte's species, although 

 very rare, appears to be the better known of the two, we 

 think it advisable in the present state of our knowledge to 

 consider it separately. A full description of C. ortlwgonum 

 is given in the appendix to this division of the genus 

 Cosmarium. 



58. Cosmarium notabile Breb. 

 (PL LXVI, figs. 15, 16.) 



Cosmarium notabile Breb. Liste Desni. 1856, p. 129, t. 1, f. 15; De Bary, 



Conj. 1858, t. 6, f. 53, 53 ; Arch, in Pritch. Infus. 1861, p. 733 ; Eabenh. 



Flor. Europ. Alg. Ill, 1868, p. 173 ; Kirchn. Alg. Schles. 1878, p. 152 ; 



Wolle, Desni. U.S. 1884, p. 66, 79, t, 16, f. 11 ; Eoy & Biss. Scott. Desm. 



1894, p. 169 ; Nordst. Index Desmid. 1896, p. 183 ; West & G. S. West, 



Alg. S. England, 1897, p. 488 ; Alga-fl. Yorks. 1900, p. 81 ; Alg. N. 



Ireland, 1902, p. 37 ; Freshw. Alg. Orkneys and Shetlands, 1905, p. 21. 

 Didymidium (Cosmarium} notabile Reinsch, Algenfl. Frank. 1867, p. 117. 

 Penium (Sphinctopenium) notabile Gay, Monogr. loc. Conj. 1884, p. 71. 

 Dysphinctiiim notabile (Breb.) Hansg. in Oesterr. botaii. Zeitschr. 1887, 



xxxvii, p. 57 ; Prodr. Algenfl. Bohm. 1888, p. 186 ; De Toni, Syll. Alg. 



1889, p. 889. Gutw. Flor. glonow Galic. 1892, p. 123 ; SchniicUe, Beitr. 



alp. Alg. 1895, p. 348. 



Cells ratlier small, from 1J to 1-J- times as long as 

 broad, moderately constricted, sinus narrow and 

 generally open; semicells truncate-pyramidate, basal 

 angles rectangular and slightly rounded, apical angles 



