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



6. Colonies united by short gelatinous bands. 4. C. Lauterbomi. 

 6. Colonies united in extensive flat sheets. 5. C. irregularis. 



1. C. RBCTANGULARis(A. Br.)Gay, 1891, p. ioo, PI. XV, fig. 

 151 ; W. & N., Alg. Exsicc. Nos. 53, 171 ; Staurogenia rect- 

 angularis A. Braun, 1855, p. 70. Cells 4-6 X 5-7 /*, oval or 

 oblong, united in fours, touching near the outer end, or curved 

 and touching near the middle. Greenland, Mass., Wis. Europe. 



2. C. CRUCIKERA (Wolle) Collins, 1909, p. 170; Staurogenia 

 frua/era Wolle, 1877, p. 140 ; S. cruciata Wolle, 1887, p. 171, PI. 

 CLVII, figs. 9-1 1. Cells rhomboidal, equilateral, with incurved 

 sides and rounded angles, four forming a colony of the same form 

 as the individual cell ; " cells with a cruciform marking on the 

 surface." Wolle. 



Since Wolle's imperfect description and rudimentary figures, 

 no information has been obtained as to this species, until its re- 

 discovery by G. M. Smith, who found it in Tenderfoot Lake, 

 Wis., June, 1917. 



3. C. QUADRATA Morreii, 1830, p. 413, PI. XV, figs. 1-5 ; 

 including C. triangulaiis (Chodat) Schmidle, 1900, p. 234. 

 Cells quadrate, 3-4 /* square, with more or less rounded corners, 

 or subcircular, united in regular, quadrate, 4-celled colonies. 

 Wis., G. M. Smith. /:/</>/>'. 



4. C. LAUTKRHORNI (Schmidle) Chodat, 1902, p. 206, fig. 

 127; Staurogenia Lauterbomi Schmidle, 1896, p. 192, fig. i. 

 Cells arranged as in C. rectangularis, 6 X 3-4 M, the 4 celled 

 colonies united in groups of 8-32 by short gelatinous projections. 

 Wis., G. M. Smith. l:urope. 



5. C. IRREGULARIS Wille, 1898, p. 302. Cells 6-14 X 4-9 M 

 united as in C. rectangnlaris, but more irregularly, and more 

 cells to a colony, 45-90 /* diam. ; the colonies united by gelatine 

 into a flat or undulate expansion. Wis., G. M. Smith. Europe. 



6. C. TRTRAPBDIA ( Kirchner) W. & G. S. West, 1902. 

 p. 62; Pascher, 1915, p. 174, fig. 251 ; Staurogenia f tclrapedia 

 Kirchner, i88o,'Pl. II. fig. i. Colony 4-celled, plane, quad- 

 rangular, cells in close contact, each a right-angled triangle, 

 the outer side (opposite the right angle) somewhat concave, 

 cells about 5-10/1 long; colonies united 4-16, individual cells 

 assuming a quadrangular shape before division, the division 

 diagonal. Chromatophore parietal, without pyrenoid. Wis., 

 G. M. Smith. Europe. 



7. C. PENRSTRATA Schmidle, 19003, p. 234 ; Pascher, 1915, 

 p. 174, fig. 252. Cells trape/iform, 6-8 X 2-3 /*i colonies 4-celled, 



