398 
Staurastrum crescentum Hast. p. 153, t. XLII, fìg. 8-11.— - Se- 
inicells subelliptic, or somewhat hexagonal, base truncate, convex, 
uudulate; superior lateral margins each with three teeth or verru- 
ca3, thè upper two truncate; apex truncate undulate; each lateral 
angle furnished with two, or rarely three, diverging aculei, rarelv 
unarmed; end view triangular, side sinuous concave, sometimes fur- 
nished with a subulate spine near thè angles; angles suddenly atte- 
nuate, rouuded and usually furnished with two, sometimes three 
aculei, rarely unarmed ; -center of triangle smooth, surrounded by three 
pairs of crescentric teeth in a wide circle, these are surrounded by 
others, so that each liinb of thè triangle bears five crescentric teeth, 
two, two and one, all within thè margin, thè last one sometimes in* 
distinct or obsolete. Diam., without aculei, 45-50 u. 
Die Tafeln L1V-LXII aus «Fresh-water algae» des Verfasses 
sind in diese Auflage eingefiihrt; uberdiess sind zwei Tafeln neu, 
nàmlich XLII u. XLIII. Sie enthalten folgende Figuren: Micrasie- 
rias Swainei Hast., M. Kitchelii Wolle var., Xanthidium antilo- 
pceum v. truncàium Hast., Staurastrum megalonotum v. obtusum 
Hast., S. crescentum Hast., Euastrum verrucosum var. simplex 
Joshua, S. saxonicuìn v. pentagonum Wolle, Euastrum Hasting- 
sii Wolle, Micrasterias radiosa v. puncta/a West, Xanthidium an - 
tilopceum v. canadense Josh., Cosmarium Regnesi Reinsch, Siau * 
rasirum angulatum West, Sphcerozosma serraium Bail., S. ( Ony - 
chonema ) Nordstedtiana Turn., Cosmarium Meneghina f. ocian- 
gularis v. semplicissima Wille, C. Iceve v. septentrionale Wille, tìo * 
natozygon sex -spini ferum Tura., Calocylindrus Cucurbita (Bréb.) 
Kirch., Cosmarium Cordanum Bréb., Closterium Braunii Reinsch, 
C. subdirectum West, C. rostratum v. brevirostratum West, C. 
Leibleinii v. curtum West. 
