A synopsis of the New England species of Tetmemorus’ 
JosEPH AUGUSTINE CUSHMAN 
With the present records all four species of Ze¢memorus found 
in the British Isles are known from New England. The species 
of Tetmemorus are not striking in their appearance and one study- 
ing plankton rarely meets with them. In New England the spe- 
cies appear to be mostly found in sphagnum pools and also as a 
rule seem to be more common at an elevation, being found very 
abundantly in certain mountain ponds with sphagnous borders. 
The figures given by Wolle were poor and in some cases were 
referred to the wrong species. The corrected synonymy for the 
various species is given. The measurements are from New Eng- 
land specimens only. Records for which specimens have been seen 
are followed by an exclamation point. While based upon New 
England material this should cover the whole northeastern United 
States. 
TETMEMORUS Ralfs, 1844 
Cells usually fusiform-cylindrical, straight, with a slight median 
constriction, and a narrow incision at the center of the apices: 
cell circular or elliptical in end view : cell-wall usually punctate 
or slightly scrobiculate : each semicell with a single chloroplast, 
with a central row of pyrenoids. 
1. Termemorus Bréprssoni (Menegh.) Ralfs 
Closterium Brébissonti Menegh. Linnaea 14: 236. 1840. 
Tetmemorus Brébissonii Ralfs, Ann. Mag. Nat. Hist. 14: 257. pl. 
8. f. 1. 1844. — Brit. Desm. 145. A. 24. f. 1, a, 6, ¢. 1848. — 
Wolle, Desm. U. S. gt. pl. 20.f- 4 2: pl. 50. f. 36. 1884. 
Cells subcylindrical, attenuate toward the apices, much more 
so in side view, about 6 times as long as wide ; apices broadly 
rounded in both front and side views ; cell-wall minutely punctate 
in longitudinal lines ; chloroplasts with 4-5 pyrenoids. 
Length 189-236 #: breadth 34-37 #: isthmus 20-31 #4. 
Marne: Orono (W. West). New HAMPSHIRE = North Wood- 
stock! MassacHusEtts ; Guilder Pond, Mt. Everett, Mount 
599 
