16 P. T. CLEVE, ON SOME NEW DIATOMS. 
This form has the appearance of S. Smithii Grun., but is larger and has coarser 
strie (being 28 in 0,01 mm. on S.Smithii) not so parallel as in S$. Smetha. 
Schizostauron Gro. 
1. Schizestauron Crucicula Grey. 
Strie oblique, fine, 25 in 0,01 mm. Stauros bifid with very divergent branches, 
reaching the margins. 
Length 0.03 mm. Breadth 0,009 mm. 
Pe ei ae ee 
Merrimac River U. St. on Chara, very rare in a gathering sent by Mr. O. Norp- 
STEDT. *) 
Nitzschia W. Sm. 
1. Nitzschia ocellata Cu. 
This species has already been described in Cr. et Gren. Arct. Diat. p. 80. The 
frustule is panduriform; the keel central with 8—10 puncta in 0,01 mm. The striz 
are fine, 22 in 0,01 mm. composed of small, elongate puncta. The striae are sharper 
and more distant in the centre of the valve. The whole valve is covered with large 
scattered puncta sometimes arranged in irregular, transverse lines. 
Length 0,08—0,1 mm. Breadth of the frustule 0,027 mm. at the constriction 
0.018 mm. 
Pl. IV, fig. 47, *°°°/,, a. valve, 6. frustle. 
Balearic Islets (Dr. Sé6pERLUND). Cx. et Monn. Diat. N:o 154—155 rare. 
This species is placed by Grcnow in his section Pseudoamphiprora, very nearly 
to Perrya Kirton. 
2. Mitzschia prelonga Cu. 
This species has already been described in CL. et Grey. Aret. Diat. p. 85. The 
frustules are extremely long and slender, slightly arcuate, linear, with obliquely cuneate 
ends. Keel almost central, with about 5 puncta in 0,01 mm. The striw are strong, 
16 in 0,01 mm. 
Length 0,25 mm. Breadth 0,009 mm. 
Pi, EX, te, 8 og Oo es 
Balearic Islets not rare (Dr. F. SéDERLUND). 
1) In printing this paper I have been informed by Mr. Grexow that he has found the same form abun- 
dantly in pools of the Rio Purus, Brazil, and that he has named it in Linnean Society Journ. of May 1880 
I consequently adopt his name. 
