74 p. T. CLEVE, SYNOl'NIS OF TIIK NAVICULOID DIATOMS. - 



Var. rohusta Grun. (187S). — Broader, more clavate. — G. here. v. rob. GtRUn. Casp. Sea 

 Alg. ]). 12 PI. Ill f. 3. 



Fi'esh water: Kamtschatka (Grun.). 



Var. chirnfa CJl. — Broadest at the u})per, rminded-tnuicate end. L. 0, ii; B. 0,ti:! mm. 



Fresh water: Pitt River, Col. (Gro\e Goll.)! 



Naviculse Luxuriosse Cl. 



Valve of elliptical outline, with depressed areas on both sides of the median line, separated 

 by a more or less broad farrow from the marginal part. Axial and central area uniting in a 

 narrow space around the median line. Structure: marginal, short stria; and on the depressed areas 

 large distant puncta forming more or less regular longitudinal rows. 



Only a few forms of this section are known, and it seems at present impossible to decide as 

 to their affinities. They have some resemblance to Diploncls nitcseois. The short marginal striae 

 are apparently smooth, but in a specimen of N'. Inxnrinsa from Gliina 1 liave seen in the marginal 

 furrow rows of distinct puncta in continuation of the marginal striic. 



1. N. luxuriosa Grey. (1862). — V. elliptic-lanceolate," with obtuse, sometimes cuneate, 

 ends. L. 0,oo to 0,o9; B. 0,025 to 0,035 mm. Axial area narrow linear, slightly dilated in the 

 middle. Stritie marginal, slightly radiate at the ends, 7 to 9 in 0,oi mm. Furrow with rudi- 

 mentai'y, sometimes distinctly punctate, stritc. Depressed lateral areas large with 3 to 5 longi- 

 tudinal rows of large puncta straight, or curved towards the median line. — Nav. luxnriosa Grev. 

 T. M. S. XI p. 18 PI. I f. 10, 11. Nav. lux. var. nmeata Brun. D. esp. n. p. 3.5 PI. XVI f. 3. 



Marine: N. S. Wales (Grev.), China! Japan (Brun Coll.)! 



2. N. decora Grove and Sturt (1887). — V. elliptical, with obtuse ends. L. 0,075 to 0,125; 

 B. 0,o;i to 0,04 5 mm. Median line straight; its terminal fissures turned in the same direction. 

 Axial area distinct, linear, slightly dilated around the nodule. Marginal stritB 7 in 0,01 mm., 

 apparently smooth, slightly radiate. Furrow crossed by faint striae. Areas large, coarsely punctate; 

 puncta forming 5 to 6 irregularly undulating longitudinal rows, or somewhat scattered. — Grove 

 and Sturt Quek. M. Cl. Ill (2) p. 133 PI. X f. 13. A. S. Atl. CLXXIV f. 27. 



Marine: Oamaru, New Zealand, fossil! 



3. N. trilinoata Grove and Sturt (1887). — V. elliptic-lanceolate. L. 0, 1; B. 0,033 mm. 

 Axial area narrow, slightly dilated towards the middle. Stride (! in 0,oi mm. ci'ossed by two longi- 

 tudinal blank bands, so that each half of the valve seems to bear three longitudinal I'ows of 

 elongate, coarse puncta. — Grove and Sturt Quek. M. Cl. Ill (2) j). 132 PI. X f. 8. 



Marine: Oamaru, New Zealand, fossil! 



Naviculse Nicobaricse Cl. 



Valve elliptical in outline. Median line with approximate central pores and large comma- 

 like tei-minal fissures, bordered on both sides by a longitudinal row of large, sometimes conflvient 

 jiiiiicta. Axial and central areas united in a lanceolate space. Structure apparently smooth, distant 

 striic, radiate tliroughout. 



This group comprises only two known species N. Nicobarica and N. Np, of doubtful affinity 

 to and other species. They have some i-esemblance to certain Diploneis forms, Imt the central and 

 terminal nodules are very different. They seem to me provisionally to l)e nearest akin to Diploii. 

 hioriiJa/d and N. forcipafa, altliough the relation is a distant one. 



