30 p. T. CLEVE, SYNOPSIS OF THE NAVICULOID DIATOMS. 



4. 



j Marginal cellules of unequal size . . ... . . . . D. panduriformis 



\ — — equal — ... . . . 5. 



f Cellules of the valve 9 in 0,oi mm. . . D. subconstrieta Cl. 



' \ — — — 17 — . . D. Pantocseki Cl. 



„ I Segments narrow, linear . . ■ I), rugosa Temp. a. Bk. 



I — broad — ■ . . 7. 



_ I Marginal cellules about 5 in 0,0 1 mm I), marginata Lewis. 



' \ — — — 10 — D. mastogloides Pant. 



1. D. navicnlacoa Cl. (1890). — V. elliptic-lanceolate. L. 0,09; B. 0,23 mm. Central nodule 

 very small, surrounded by a moderately large, orbicular area. Terminal fissures indistinct, turned 

 in the same direction. Cellules of tlie valve of about equal size, 10 in 0,oi mm. Transverse striee 

 not seen. — Cl. Diatomiste I p. 15. Icon. n. PL V f. 34. 



Marine: Pensacola, Florida! 



This species, of which I have seen one specimen only, seems to be extremely rare. 



2. D. jamaicensis Grbv. (1868). — V. strongly constricted in the middle with cuneate or 

 elliptic-lanceolate segments and obtuse ends. L. 0,08 to 0,12; B. 0,024 to 0,032, at the constriction 

 0,013 to 0,02 mm. Terminal iissures in opposite directions. Cellules of the valve about 11 in 0,oi 

 mm., obscure around the central nodule. Transverse strise 24 to 27 in 0,oi mm. — Nav. jamai- 

 censis Grev. T. M. S. XIV p. 126 PI. XII f. 23. Nav. tortuosa Leud.-Fortm. D. de Ceylan p. 34 

 PI. II f. 26 1879 -Mastogloia? reticulata Peragallo D. de Villefr. PL II f. 10, 1888. — PL V f . 32. 



Marine: Mediterranean Sea! Adriatic! Eed Sea (Van Heurck Coll.)! Ceylon! Sumatra (Deby 

 Coll.)! Cebu (Grove Coll.)! New Guinea (Grove Coll.)! West Indies (Grev.). 



Var. gigantea Cl. — L. 0,21; B. 0,o4s at the constriction 0,022 mm. Cellules about 16 in 

 0,01 mm. Striae 23 in 0,oi mm. 



Marine: Oamaru, New Zealand, fossil (Grove Coll.)! — PL V f. 35, 36. 



3. D. marginfita Lewis (1861). — V. strongly constricted in the middle. L. 0,8 5 to0,i8; 

 B. 0,024 to 0,044, at the constriction 0,oo8 to 0,022 mm. Segments cuneate to elliptical, with ob- 

 tuse extremities. Terminal fissures in opposite directions. Marginal cellules of equal size, 4 to 5 

 in 0,01 mm. Cellules of the valve 8 to 12 in 0,oi mm. 



The following forms may be distinguished. 



., j Marginal cellules forming a broad band ... Var. spectatissima. 



' \ — — — narrow — 2. 



f Valve about 3 times longer than broad 3. 



Var. intermedia. 



S. I — 4 - — — .».. .„.„,„c 



I — 5 to 6 — — — 4. 



{Segments cuneate Var. typica. 

 — elliptic-lanceolate Var. Janischii. 

 — elliptical with rounded ends Var. Clevi. 



to 0,12 mm Var. commutata. 



Var. gigantea. 



j L. 0,11 

 I L. 0,18 



Var. typica Cl. — V. about 3 times longer than broad, deeply constricted, with cuneate, 

 obtuse segments. L. 0,o85 to 0,i5; B. 0,o24 to 0,037, at the constriction 0,oo8 to 0,oi5 mm. 

 Marginal cellules 4 to 5 in 0,oi mm., forming a narrow band; cellules of the valve 8 to 12 in 0,oi 

 mm., forming irregular, transverse rows. Transverse strise 26 to 27 in 0,o: mm. — Navicula mar- 

 ginata Lewis Proced. Acad. Nat. Sc. Philad. 1861 p. 64 PL II f. 1. Nav. strangulata Grbv. T. M. 

 S, XIV p. 126 PL XII f. 24; 1866. — Nav. reticulata Grxin. Hedwigia VI p. 26. Mastogloia? 

 reticulata Grun. M. M. J. 1877 p. 175 PL CXCV f. 4. Navic. Kossuthii Pant. 1 p. 26 PL XVI 

 f. 120; 1886. Dictyoneis marginata Cl. Diatomiste I p. 16 1890. A. S. Atl. PL CLX f. 20 23 

 28, 29. CLXXXVIII f. 47. ' ' 



