44 TUFTS COLLEGE STUDIES, VOL. IV, No. 7 



Var. IRRBGULARIS (Wille) G. M. Smith, 19163, p. 448, PI. 



XXVIII, figs. 59-62 ; 5. bijugatus forma irrcgularis Wille, 19033, 

 p. 92, fig. 4. Cells irregularly arranged, alternately or in two 

 series, 7.5-10 X 3.5-6 /*. Wis., G. M. Smith. Europe. 



7. S. ARCUATUS Lemmermann, 18993, p. 112, PI. I, figs. 

 2-4; G. M. Smith, 19163, p. 449, PI. XXVI, figs. 19-20; 



XXIX, figs. 94-98 ; XXX, figs. 99-100. Colonies 4-i6-celled, 

 usually 8, more or less curved, small openings between cells ; 

 cells in two series, oblong-ovoid or subangulate, 9-15 X 5-9 /*. 

 Wis., G. M. Smith. Europe. 



Var. PLATYDISCA G. M. Smith, 19163, p. 451, PI. XXX, figs. 

 101-105. Colony usually 8-celled, cells in two series in one 

 plane, with very small openings, 8-n X 4.5-6/4. Wis., G. M. 

 Smith. 



8. S. DENTICULATUS Lagerheim, 1882, p. 61, PI. II, figs. 

 13-17; G. M. Smith, 1917, p. 452, PI. XXVI, fig. 23. Colo- 

 nies 4-celled, cells alternately or subcruciately arranged, ovoid 

 or ovoid-oblong, apices rounded, with two small teeth, 7-15 X 

 5-1 1 ft. Wis., G. M. Smith. Europe. 



Var. I.INEARIS Hansgirg, 1888, p. 266 ; Collins, 1909, p. 169 ; 

 G. M. Smith, 19163, p. 454. 



9. S. ACUTIFORMIS Schroder, i897b, p. 45, PI. II, fig. 4 ; 

 G. M. Smith, 19163, p. 456, PI. XXVI, figs. 28-29; XXIX, 

 figs. 84-89. Colonies 2-8-celled, cells uniseriate, fusiform, end 

 cells with 4 longitudinal ridges, median cells with 2 each ; 

 cells 16-22 X 5.5-8 /. Wis., G. M. Smith. Europe. 



The number of ridges can best be seen in cross section ; a 

 side view shows usually only one ridge to a cell. 



10. S. BRASILIBNSIS Bolllill, 1897, p. 22, PI. I, figS. 36-37 ; 



G. M. Smith, 19163, p. 458, PI. XXVI, figs. 30-31. Colonies 

 4-8-celled, cells in a single straight series, oblong, obtuse, each 

 with minute teeth at pole, and four very slender longitudinal 

 ridges, 11-24 X 8-20/4- Melrose, Mass., C. Bullsrd ; \\ is . 

 G. M. Smith. Africa^ Asia, So. Am, rim. l-'.nrope. 



n. S. ARMATUS (Chod3t) G. M. Smith, 19163, p. 460, PI. 

 XXVIII, fig. 53; XXIX. figs. 90-93; XXX, figs. 109-110; 

 S. Hystrix var. armalus Chodat, 1902^ p. 215, fig. 140. Colo- 

 nies 2-8-celled, cells in 3 straight or subalternate series, ovoid 

 or oblong-ovoid, end cells with a spine at each pole, median 

 cells spineless ; all cells with more or less distinct fine lateral 

 ridges; cells 7-14 X 4-? M, spines 5.5-7 /t long. Wis., G. M. 

 Smith. Europe. 



