SOME DESMIDS OF THE UNITED STATES. 315 
probably S. iotanum, are precisely similar to those we have 
noticed from England and the United States, and which we have 
always thought to be Wolle’s species. As Wolle's description is 
too meagre and somewhat incorrect, and his figures very indis- 
tinet, we feel it desirable to describe and figure this species. 
S. minutissimum et inconspicuum, paullo latius quam longum 
(cum processibus), modice constrictum, sinu parvo acutangulo 
aperto; semicellule subrectangulares, angulis basalibus sub- 
rectangularibus et non rotundatis, apicibus levissime convexis, 
angulis superioribus in processus longos divergentes bi- vel tri- 
nodulosos productis, apicibus processuum emarginatis; a vertice 
vise triangulares, lateribus subrectis, angulis in processus longos 
nodulosos productis; membrana glabra. 
Long. s. proc. 8-10 p, e. proc. 13-20 u; lat. s. proc. 6-9 y, 
e, proc. 13-21 p; lat. isthm. 3:5-4 p. (Pl. 18. figs. 14, 15.) 
Hab. Bridgeport, Conn. (H. J. no. 527). 
143. STAURASTRUM BICORONATUM, Johns, in Bull. Torr. Bot. 
Club, xxi. (1894), p. 290, t. 211. f. 9. 
Hab. Whitmore Lake, Mich. (H. J. no. 454). Malaga, New 
Jersey. 
b [^ 
Fig. 6.—a, S. incisum, Wolle, abnormal form, x 600. b. Ditto, X 700. 
c. S. pulchrum, Wolle, X400. d, e, f. S. distentum, Wolle, x520. (fis 
Somewhat oblique.) 
V4. S. mvcisum, Wolle, Desm. U.S. p. 132, pl. 41. ff. 12-14. 
A figure is given of a normal (fig. xylogr. 6 5) and an abnormal 
