18 p. T. CLEVE, SYNOPSIS OF THE NAVICULOII) DIATOMS. 



f. 352 (1856). Schizon. neglectum V. H. Syn. PI. XV f. 37. N. yracilis v. schizon. V. H. Syn. p. 83 

 PI. VII f. 9, 10. 



Fresh water: England! Belgium (V. H.). 



N. gracilis is very similar to larger varieties of N. cincfa and to some forms of N. radiosa 

 from which it may be distinguished by its less radiate striae, jand larger, transverse central area. 



12. N. peregriiia Eiib. (1843). — V. lanceolate with obtuse ends. L. 0,o8 to0,i5; B. 0,o2i 

 to 0,0 2 8 mm. Axial area distinct, narrow. Central area large, somewhat transverse, subrectan- 

 gular. Striee in the middle 5 to 6 in 0,oi mm. radiate, and frequently alternately longer and 

 shorter, towards the ends transverse, and at the ends (8 in 0,o imm.) convergent, distinctly lineate'; 

 lineolee about 25 in 0,oi mm. — Finn, pereg. Ehb. Am. 1: i f. 5, 6. "W. Sm. B. D. I PL XVIII 

 f. 170. N. pereg. KtJTZ Bac. p. 97 PI. 28 f. 52. A. S. Atl. XL VII f. 57—60. 



Brackish water: Sea of Kara! Baltic! North Sea! Saxony! Adriatic (Grun.), Arctic America! 

 Greenland! Atlantic coasts of United States! Argentina! Cape Wankarema! Japan! Batavia! 



Var. kefvingensis Ehb. (1840). — Smaller. L. 0,o4 4 to 0,o9 mm. Striee 7 (middle) to 8,5 

 (ends). — Finn. kefv. Ehb. Ber. 1840 p. 20 (accord, to Kutz). M. G. X: 2, f. 4, 5. Nav. Icefv. 

 KtJTZ Bac. p. 97 (1844). A. S. Atl. XLVII f. 61, 62. 



Brackish water: Firth of Tay! Franzenbad, fossil! 



Var. polaris Lagst. (1873). — V. subelliptical, with broad, obtuse ends. L. 0,o5i to 0,072; 

 B. 0,0 14 to 0,0 16 mm. Striee 6 (middle) to 8 (ends) in 0,oi mm. — N. polaris Lagst. Spitsb. D. 

 p. 24 PI. II f. 3. Boh. p. 33. 



Brackish water: Spitsbergen! Beeren Eiland (Lagst.), Bohuslan (Lagst.). 



Var. calcuttensis Grun. Ms. — V. lanceolate. L. 0,o5 to 0,06;B. 0,oi7 mm. Striee 9, lineolee 

 21 in 0,01 mm. Axial area unilateral, not dilated in the middle. Central area small, also uni- 

 lateral. — PI. II f. 2. 



Brackish water: Calcutta! 



Var. Meniscus Schum. (1867). — V. elliptic-lanceolate. L. 0,o36 to 0,o66; B. 0,oi to 0,oi9 

 mm. Striee 7 to 8,5 in 0,oi mm. — N. Menisctis Schum. P. D. II N. p 55 PL II f. 32 {N. Sam- 

 hiensis f. 37? N. aperta f. 49, N. Cyprinus f. 50?). Grun. A. D. p. 33. A. S. Atl. XLVII f. 47 

 (without name). N. pereg. v. M. V. H. Syn. p. 82 PL VIII f. 19. 



Brackish water: Sea of Kara (Grun.). Baltic (Schum., Grun.), Konigsberg, fossil! Cuxhaven 

 (Atl.), C'ape Wankarema! 



Forms with asymmetrical axial area occur at Cape Wankarema. 



Var. Menisculus Schum. (1867). — V. elliptic-lanceolate, frequently slightly rostrate. L. 0,oi8 

 to 0,04; B. 0,0 1 to 0,011 mm. Axial area indistinct; central area small. Strife 9 to 12 in 0,oi 

 mm., finely lineate. — N. Menisc, Schum. P. D. II N. p. 56 PL II f. 33. N. pereg. v. 3Ieniscultis 

 V. H. Syn. p. 82 PL VIII f. 20, 21, 22. N. Gastrum v. Vpsaliensis Grun. in CI. M. D. N:o 242. 

 N. pereg. menisculus f. Upsaliensis V. H. Syn. p. 82 PL VIII f. 23, 24. N. pressa Pant. Ill 

 PL XXIV f. 362 (1893)? 



Fresh and slightly brackish water: Sweden! Baltic! Konigsberg and Domblitten, fossil! Bel- 

 gium (V. H.), France (Paris, Normandy)! Saxony! Vienna (Grun.), Argentina (Sierra Velasco)! 



By the var. Menisculus N. peregrina seems to pass into N. cryptocephala var. vcneta. 



13. N. Haueri Grun. (1882). — V. lanceolate, with obtuse ends. L. 0,o8 to 0,12; B. 0,oi7 to 

 0,0 19 mm. Axial area narrow. Central area large, transverse. Striee 8 in 0,oi mm. radiate and 

 more distant in the middle, convergent in the ends, finely lineate, and crossed on both sides of the 

 median line by a narrow, blank area. — F. D. Ost. Ung. p. 143 PL XXX f. 48. Pant. Ill 

 PL VIII f. 135. 



Brackish water: Hungary, fossil (Dubravica, Grun., Bory)! 



This species, distinguished by the blank band across the striae, is nearly akin to N. peregrina. 



