98 P. T. CLEVE, SYNOPSIS OF THE NAVICUI.OID DIATOMS. 



D. nitescens is remarkable for the week development of the central nodule, the horns of 

 whicl) are scarcely distinct. In this respect it comes near to D. inscripta Cl. On corroded speci- 

 mens the alveoli are indistinct. 



72. D. (lalniatica Grun. (ISfiO). — V. slightly constricted, with cuneate segments. L. 0,o.ö8 

 to 0,062; B. 0,0 14 to 0,017; at the constr. 0,oi2 to 0,oi4 mm. Central nodule small, rounded 

 elongated; its horns indistinct, close to the median line. Furrows narrow, not dilated in the middle, 

 crossed by faint costaj. Costse 8 in 0,oi mm., alternating with double rows of alveoli. — Nav. 

 (Mm. Grun. Verh. 1860 p. 525 Pl. III f. 14. A. S. Atl. VIII f. 58, 59. .Y. Hornigii Paxt. III 

 Pl. XVI f. 241 (1893)? 



Marine: Morocco! Balearic Islands! Adriatic (Grun.), Bab el Mandeb! Macassar Straits! 

 Campeachy Bay! 



Var. Vulpecula A. S. (1875). — V. deeply constricted, with semilauceolate segments. L. O.or, 2; 

 B. 0,017; at the constr. 0,oi2 mm. Central nodule small, its horns indistinct. Furrows linear, 

 moderately broad, near the horns with traces of the costse. Transverse costfe parallel, 8 in 0,oi mm., 

 alternating with indistinct (donble?) rows of puncta. — Nav. Vulp. A. S. Atl. XII f. 5(). 



Marine: Celebes (Atl.), Java! 



73. D. Mauleri Brun. (1880). — V. enii)tical. L. 0,037 to 0,0.5; B. 0,oi3 to 0,oi5 mm. 

 Central nodule large, rounded; its horns indistinct, close to the median line. Furrows broad, for- 

 ming a narrow elliptical space, half as wide as the valve, with two rows of large puncta. Costse 

 7 in 0,01 mm. alternating with doiible rows of alveoli, 10 in 0,oi mm. — Nar. Ulauleri Brun. D. 

 des Alpes p. 77 Pl. I f. 18. D. espéces n. p. 35 Pl. XV f. 7. 



Lacustrine: Lac Leman! Sahara (Brun), Bottom-mud from A^ettern! Of frequent occurrence 

 in the Baltic dejjosits of the Ancylus-epoch. 



Var. borussica Cl. (1882). — L. 0,025 to 0,037; B. O,oii to 0,oi2 mm. Costse 7 to 8 in 

 0,01 mm. alternating, with (single?) rows of indistinct alveoli. — Nnr. borussica Cl. Phys. Oek. 

 Gesellsch. zu Königsberg XXII p. 139. — A. S. Atl. VIII f. 17, 19. Nar. Mauleri Pant. III 

 Pl. VII f 105; Pl. IX f. 150. 



Slightly brackish water: Gulf of Bothnia at Xedre Kalix! Domblitton. Prnssia fossil! 

 Hammer Moor (Atl.). 



74. D. Debyi Pant. (1886). — V. lanceolate, with obtuse ends. L. 0,i ; B. 0,03 mm. Cen- 

 tral nodule rounded qnadrate; its horns slightlj' divergent in the middle, approximate. Furrows 

 very broad, with a row of strong puncta (reduced costfe). Costse slightlj' radiate, 4 in 0,oi mm., 

 alternating with rows of alveoli. — Nar. Debyi Pant. I p. 23 Pl. XV f. 136. 



Marine: Szåkal, Hungary, fossil (Pant.). 



Var. elliptica Cl. — V. narrow elliptical. L. 0,i; B. 0,035 mm. Furrows broad. Costse. 5 

 in 0,01 mm. continned across the furrows and alternating with double rows of small alveoli. • — 

 Pl. II f. 4. 



Marine: Red Sea (Deby Coll.)! 



75. D. geinmata Grev. (1859). — V. broad, linear, with rounded or cnneate ends and pa- 

 rallel or slightly concave margins. L. 0,os5 to 0,24; B. 0,o3 to 0,005 mm. Central nodule large, 

 quadrate; its horns parallel, closely approximate to the median line. Furrows broad, linear, fiUing 

 a third or less of the surface of the valve. Costa? 3 to 6 in 0, 01 mm., alternating with double 

 rows of twice as close alveoli. Along the horns of the central nodule is a row of short, hut 

 strong costfe. 



Var. fossilis Pant. (1886). — V. slightly constricted in the middle. L. 0,i6 to O.24; B. O.045 

 to 0,065 mm. CostcB 3 in 0,oi mm. — A. S. Atl. LXX f. 74. Nar. qcnimata var. fossilis Pant. I 

 p. 25 Pl. XX f 181. 



Marine, fossil: Hungar}- (Deb}' Coll.)! Moravian Tegel! Moron (Atl.). 



