286 
\ 
single specimen at Waverly, Mass. On the other hand, some so-_ 
called rare species have proved rather abundant, at least in certain 
localities. 
Of the filamentous forms the most interesting were Onychonema 
Jiliforme (Ehrenb.) Roy and Bissett, and.O. /eve Nordst. at Bridge- 
port, and O. leve, var. micracanthum Nordst. from Michigan. The 
spines of the last named were often not so large as shown in the | 
drawing (Fig. 15). Hyalotheca undulata Nordst. was found 
(Conn.) having a diameter of about 7 “ and with the sheath in- 
conspicuous if present. It thus resembles the type more closely 
than Wolle’s description. ; 
Spherozosma pulchellum (Arch.) Rab. is frequent in Connectl- 
cut, as is another species, undoubtedly S. Wadllichii Jacobsen. It 
agrees well with Wallich’s description and figures * of S. excavalum 
var. g. It was very abundant last season in the locality mentioned, 
and across the Sound in New York, and was also found in Michi- 
gan. Dimensions, length 12-14 “, diameter 10-12 #. 
Spirotenia obscura Ralfs. was found near Oyster Bay, N. Y., 
in 1893. The specimens were in fine condition, and averaged 25/ 
in diameter, thus being of about the same size as European 
specimens. Wolle gives the diameter 8-15 /. : 
Of Closterium the most noteworthy species collected are hs 
lineatum Ehrb. var. costatum Wolle (Conn.), CZ. didymotocu " ie 
Corda (Conn.), and Cl. malmvernianum DeNot (Mich.). The _ 
second agrees perfectly with descriptions and figures of the species 
named, but the diameter of the cells is 45-52 “ Delponte figures - 
it from Italy of similar form and size. The last may be 
Ehrenbergit Menegh. var. brasiliense Nordst., for there seems wise ss 
difference between the two forms. The membraneis finely — ; 
diameter of cell 92 “, and length eight times as great. It has ai 
before been reported from the United States. 
My specimens of Exastrum gemmatum Breb., do not resem 
Wolle’s figures very closely, but are much like those of Ralfs. 
is common in Connecticut material. 3 . 
Euastrum binale Ralfs. var. insulare Wittr., of the form a“ | 
in Fig. 8, is quite common in Michigan and Connecticut materi®” 
le se 
He 
* Annals and Mag. of Nat. Hist., Ser. 3,5: 192, pl. VIL, fig. 45 (1860). . i 
