35° 
The Ohio Naturalist. 
[Vol. V, No. 7, 
Tetmemorus laevis (Kutz.) Ralfs. Forma. 
Length 210/c breadth 34/z. Frequent. 
Although from the measurements given for this species it would seem 
to be either nearer T. Brebissonii or T. granulatus, the form is decid- 
edly nearer that of T. laevis and the cell wall is smooth or ver}’’ finely 
punctate. 
Euastrum verrucosum Ehrenb. 
Length 72/i: breadth breadth of apical lobe 28/i; isthums 15/t. 
Very common, a somewhat compressed form of the species. 
Micrasterias Americana (Ehrenb.) Ralfs. Forma. 
Length 149/x: breadth 127/i: breadth of apical lobe 59/i: breadth of 
isthusm 27;/. Common. 
This is a peculiar form with the apical lobe spreading rapidly with its 
base deep sunken in the median portion of the semicell and with a 
peculiar arrangement of the teeth of the end lobe. The variations 
were constant in all specimens seen and the typical form did not 
appear. 
Cosmarium pseudopyramidatum Lund. 
Length 37, «: breadth 28//: Vjreadth of isthmus G.5//. Common. 
Cosmarium cyclicum Lund. 
Length 45, breadth =length : breadth of isthmus 12.5,u. 
This species is not included by Wolle in his work and is reported by’ 
Johnson among his rarities. It seems however, to be a fairly com- 
mon species in this country as it has turned up in several widely sep- 
arated localities in material I have examined. In every’ way’ the 
specimens from Youngstown were typical. 
Cosmarium Turpinii Breb. 
Length 53-58,«: breadth 47-53,«: breadth of isthmus 12.5-14,(i: thick- 
ness 34,f(. Very common at this locality’. Wolle speaks of this 
species as “not rare.” It has not yet been recorded from Xew 
England, however. 
Cosmarium Broomei Thwaites. 
Length 32,«; breadth 28,a: breadth of isthmus 9,u. Fairly’ common. 
Cosmarium Amesii sp. nov. 
Length 47./t: breadth 53,’i; breadth of isthmus 15,«. Common. 
A Cosmarium of the group represented bv C. binum Nordst., C. 
speciosum Lund., etc. End broadly truncated, slightly’ retuse. Sides 
of each semicell with ten granules arranged in pairs as are also the 
granules of the end. From the border these pairs are repeated 
inward three or four times. The central basal portion of the side of 
each semi-cell composed of a roughly’ circular series of granules 
arranged in seven vertical rows: the central one, the longest, with six 
granules, at each side of this a series of four and the outer four rows 
each with five granules. The basal angles of the semi-cells are 
broadly’ rounded. This species is named for the collector, Mr. Charles 
B. Ames. 
Staurastrum punctulatum Breb, 
Length 29, u: breadth 28,«: breadth of isthmus 7. on. Common. 
Staurastrum muticum Breb. 
Breadth 34;/. Occasional. 
In all, twenty-one varieties and forms were noted in the'collection. 
Boston Society of Natural History 
