128 Cushman : New England species of Clostekium 



1887; Desm. U. S. 50. pi. 6. f. 22. 1892. — W. & G. S. 

 West, Brit. Desm. 1 : 173. pi. 23. f. 1-3. 1904. 



Cells very elongate, about 50 times as long as wide, nearly 

 straight, very gradually attenuated to the narrow but obtuse apices ; 

 cell-wall colorless or slightly yellowish-brown, smooth or with 

 traces of a fine striation in the older specimens. 



Length 320-375 /1 ; breadth 6-8.5 f*- 



Maine: Orono (W. West). 



New Hampshire: Pudding Pond, North Conway! 



*38. Closterium aciculare T. West 



iculare T. West. Trans. Rov. Mier. Soc 



8: 153- 



7-/. 16. i860.— W. & G. S. West, Brit. Desm. 1: 174- 

 //. 26. f. 18, 19. 1 904. 



Cells very elongate, 76 times as long as wide, median portion 

 straight, ends somewhat incurved, attenuated very gradually to the 

 acutely rounded apices ; cell-wall colorless, smooth. 



Length 380/;; breadth 5 ft. (Plate 4, figure 7.) 



Massachusetts: Lake Watuppa, Fall River! 

 . Not previously reported from the United States. 



39. Closterium acutum (Lyngb.) Breb. 



Echinella acuta Lyngb. Hydr. Dan. 209. //. 69. f. G. 18 19. 



Closterium acutum Breb. in Ralfs, Brit. Desm. 177. //. 30. f- 5- 

 P 1 ' 34- /• S, a, 6, d-f. 1848. — Wolle, Desm. U. S. 44- 

 /. 11, 12. 1884. — W. & G. S. West, Brit. Desm. 1 : 177- 

 pi. 23. f. p-14. i 9 o 4 . 



Cells small, about 25 times as long as wide, somewhat curved, 

 inner margin not tumid, gradually attenuated to the acute apices ; 

 cell-wall colorless, smooth. 



Length 150/1; breadth 6 p. (Plate 5, figure II.) 



Maine: Orono (IV. 



West) 



Weston ( W. & 



* 



40. Closterium subulatum (Kiitz.) Breb. 



Frustularia subulata Kiitz. Syn. Diat. 538. pi. 13. f. /. i834- 

 Closterium subulatum Breb. in Cheval. Microscop. 272. 1^39 



— W. & G. S. West, Brit. Desm. 1 : 179. pi. 23. f. 16-19 

 1904. 



