n8 TUFTS COLLEGE STUDIES, VOL. II, No. 3 



figs. 8 & 9 ; Wittr. & Nordst., Alg. Exsicc., Nos. 958, 1373. 

 Filaments 38-45 /j. diam., cells 4-12 diam. long ; chrotnatophores 

 3, very slender, pale green, with large pyrenoids, making }4-i}4 

 turns in the cell ; fertile cells much swollen and shortened ; 

 spores. ellipsoid, 1^2-3 diam. long, diam. up to 48 p.. N. J., Pa. 



Europe. 



Our only species with replicate cell walls and three spirals ; 

 the typical form quite distinct, but connected with 5*. Hassallii 

 by the following variety. 



Var. HANTZSCHII (Rab.) Petit, iSSo, p. 13; S. Hantzschii 

 Wolle, 1887, p. 211, PI. CXXXIII, figs. lo-u ; P. B.-A., No. 

 364. Chromatophores usually 2, occasionally 3. Mass., Pa. 



Europe. 



Petit notes that in the conjugation in this variety, filaments 

 with two spirals frequently unite with filaments of three spirals ; 

 in this case the three spiral cells always function as female, 

 receiving the contents of the two spiral cells and developing the 

 spore. 



37. S. PROTECTA Wood, 1872, p. 165, PL XIV, fig. 3; 5. 

 elegans Cleve in Wittrock, 1868, p. 190; 6". calospora forma 

 gracilior Cleve, 1868, p. 26, PI. VIII, figs. 2 and 3 ; .S". calospora 

 Petit, 1880, p. u, PI. II, figs. 11-13; Wolle, 1887, p. 209, PI. 

 CXXXIII, figs. 3 and 4; P. B.-A., No. 360. Filaments 32-36 

 /x diam., cell's 6-12 diam. long; chromatophore single, slender 

 and loose, making 4-5 turns in the cell ; fertile cells little or not 

 at all swollen, not over 42 //, diam.; spores ellipsoid or cylindric- 

 ellipsoid with rounded ends, yellow at maturity, 2-3 diam. long, 

 diam. 40-42 /u. ; median membrane punctate. Fig. 8. Mass., 

 Conn., N. J., Mich. Europe. 



The only species occurring with us which has the replicate 

 cell walls and the punctate membrane. It is a beautiful object 

 under the microscope, the yellow spores with their elegant mar- 

 gin standing out strongly against the dark green filaments. 

 In Cleve's description of ^. calospora two forms are distin- 

 guished ; forma a major, forma b gracilior ; afterwards the sec- 

 ond form was raised to specific rank as .5". elegans, but this name 

 cannot stand as there is an earlier ^". elegans Bonhome, 1858, 

 p. 6. The genuine 5". calospora, S. calospora forma major of the 

 original description, appears to be unknown outside of Scandi- 

 navia, but 5". protecta seems common in this country as well as 

 in various parts of Europe. Wittrock considers .S*. elegans to 

 be the same as Vaucher's Conjugata longata, but the evidence 



