224 Rhodora (SEPTEMBER 
The mucous covering is present, causing specimens to stick to the 
slide so firmly that they are with difficulty turned over for examina- 
tion. ‘The dimensions are considerably smaller than those given by 
Wolle. 
Staurastrum pseudosebaldi Wille. Length 30 u. Diam. 61-70 p. 
Isthmus 13-15. Found frequently in the material examined. One 
specimen apparently of this same species was much broader com- 
paratively, measuring. Length 36 y. Diam. 72pm. Isthmus ro y. 
Staurastrum muticum Breb. var. minor Wolle. Length 20-25 p. 
Diam. 22-25 m. Isthmus 7 p. Common in this material and show- 
ing many zygospores. "These are of very similar character to those 
of S. mucronatum Ralfs as figured by him. Zygospore very spinose, 
spines acute at ends showing no tendency to branch. Diameter of 
zygospore without spines, 32 p. 
Staurastrum hirsutum (Ehrb.) Breb. Length 45 m. Diam. 42 y. 
Isthmus 18 y. 
Staurastrum echinatum Breb. Length 33 m. Diam, 32 p. Isth- 
mus 12 4. Slightly larger than the measurements of Wolle. More 
densely clothed with oculei but far less so than in S. Airsutum. 
About fourteen on a side in end view. 
LITERATURE ON NEw ENGLAND DESMIDS. 
Bailey, Jacob Whitman. MicroscopicaL OBSERVATIONS MADE 
IN SOUTH CAROLINA, GEORGIA AND FrLoripA. Smithsonian 
Contrib. to Knowl. ii. art. 8, pp. 27-34. Washington, 185r. 
Bennett, James Lawrence. PLANTS or RHODE ISLAND. Prov- 
idence, 1888, pp. 107—113. 
Cushman, Joseph Augustine. Dersmips OF BRIDGEWATER, 
MassacHUsETTS. Rhodora, v. 79-81, 1903. 
Dame, Lorin Low and Collins, Frank Shipley. FLORA or 
MIDDLESEX County, MASSACHUSETTS. Malden, 1888, pp. 
159—162. 
Harvey, Francis Leroy. THE FRESH WATER ALGAE OF MAINE. 
I-III. Bull. Torr. Bot. Club, xv. 135-161, 1888 : xvi. 181—188, 
1889: xix. 118-125, 1892. 
Hastings, William N. A proposep New Desmip. Am. Month. 
Micros. Jour. xiii. p. 29, 1892. 
