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



J Marginal cellules of niiequal size D. 2>anduriformi8 



\ — — equal — ö. 



- J Cellules of tlie valve 9 in 0,oi mm D. subconstricta Cl. 



17 — D. Pantocseki Cl. 



i Cellules of tlie valv 



I Segments narrow, linear D. rugosa Temp. a. Er. 



\ — broad — . . . . 7. 



j Marginal cellules abont 5 in 0,0 1 mm I), margiiiata Lenvis. 



' ) — — — 10 — D. mastogloidcs Pant. 



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

 very small, suiTounded by a raoderately large, orbicular area. Terminal fissures indistinct, turned 

 in the same direction. Celhiles of the valve of abont equal size, 10 in 0, 01 mm. Transverse strise 

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



Marine: Pensacola, Florida! 



This species, of wliich I Lave seen one specimen only, seems to be extremely rare. 



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

 elliptic-lanceolate segments and obtnse ends. L. O, os to 0,12; B. 0, 024 to 0,o32, at the constriction 

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

 mm., obscure around the central nodule. Transverse strise 24 to 27 in 0, 01 mm. — Nav. jamai- 

 censis Grbv. T. M. S. XIV p. 126 Pl. XII f. 23. Nav. torfuosa Leud.-Fortm. D. de Ceylan p. 34 

 Pl. II f. 26 1879 "Masfogloia? reticulata Peragallo D. de Villefr. Pl. U f. 10, 1888. — Pl. V f . 32. 



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

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



Var. gigantea Cl. — L. 0,2 1; B. 0,04 5 at the constriction 0,022 mm. Cellules about 16 in 

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



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



3. D. marginata Lewis (1861). — V. strongly constricted in the middle. L. 0,85 to0,i8; 

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

 tnse extremities. Terminal fissm-es in opposite directions. Marginal cellules of equal size, 4 to 5 

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



The following forms may be distinguished. 



^ I Marginal cellules formiug a broad band . . . .-._..- ^.■. .-■. ., . ■. . Var. spectatissima. 



\ — — — narrow — '.i. ...... 2. 



f Valve about 3 times longer than broad 3. 



2. ■! — 4 — — — Var. intermedia. 



\ — 5 to 6 — — — 4. 



f Segments cuneate Var. typica. 



3. ■> — elliptic-lanceolate Var. Janischii. 



[ — elliptical with rounded ends Var. Clcri. 



L. 0,11 to 0,12 mm Var. commutata. 



mm Var. gigantea. 



t L. 0,1 

 1 L. 0,1 



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

 obtuse segments. L. 0,085 to 0,i5; B. 0,o24 to 0,037. at tbe constriction 0,oo8 to O.oi.i mm. 

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

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

 ginafa Lewis Proced. Acad. Nat. Se. Philad. 1861 p. 64 Pl. II f 1. Nar. sfrangulata Grev. T. M. 

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

 reticulata Grun. M. M. J. 1877 p. 175 Pl. CXCV f. 4. Navic. Kossnthii PaxXT. I 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. CLXXXVlil f. 47. 



