'^0 p. T. CLEVE, SYNOPSIS OF TIfE NAVICULOID DIATOMS. 



J Marginal cellules of unequal size D. panduriformis 



' \ — — equal — 5. 



j Cellules of the valve 9 in 0,0 1 mm D. subeohstricta Cl. 



\ — — — 17 — D. Pantocseki Cl. 



^ j Segments narrow, linear D. rngosa Temp. a. P.r. 



\ — broad — > 7. 



_ J Marginal cellules about 5 in 0,0 1 mm D. marginata Lewis. 



I — — — 10 — D. ma^foyloidcs Pant. 



1. D. navifulacea Cl. (1890). — V. elliptic-lanceolate. L. Con; 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 the valve of about equal size, 10 in 0,oi mm. Transverse strine 

 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. jjimsiicensis Grev. (1868). — V. strongly constricted in the middle with cuneate or 

 elliptic-lanceolate segments and obtuse ends. L. 0,(i8 to 0,12; B. 0,o24 to 0,032, at the constriction 

 0,0 13 to 0,02 mm. Terminal fissures in opposite directions. Cellules of the valve about 11 in 0,oi 

 mm., obscure around the central nodule. Transverse strifie 24 to 27 in (),oi mm. — Nar. jamai- 

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

 PL II f. 26 1879 ' Mastogloia? reticulata Peragallo D. de Villefr. PL II 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. giyautca Cl. — L. 0,21; B. 0,o4.'i at the constriction 0,022 mm. Cellules about 16 in 

 0,01 mm. Stride 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. 0,8. t toO,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. 



^ I Marginal eellules forming a broad band Var. spectatisshna. 



' \ — — — narrow — 2. 



( Valve about 8 times longer than broad 3. 



2. < — 4 — — — Var. intermedia. 



I — f) to G — — — 4. 



{Segments cuneate Var. typica. 

 — elliptic-lanceolate Var. Janischii. 

 — elliptical with rounded ends Var. Cleri. 



, I L. 0,11 to 0,12 mm Var. commutatn. 



4 s 



\ L. 0,18 mm Var. ytgantca. 



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

 obtuse segments. L. 0,o85 to 0,15; B. 0,024 to 0,o37. at the constriction 0,oo8 to 0,015 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 stria" 26 to 27 in 0,oi mm. — Navicnla mar- 

 ginata Lewis Proced. Acad. Nat. Sc. Philad. 1861 p. 64 PL II f. 1. Nav. strangulata 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. Kossuthii Pant. 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. CLXXXVIII f. 47. 



