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



Var. robusta Grun. (1878). — Broader, more clavate. — G. here. v. rob. G-run. Casp. Sea 

 Alg. p. 12 PL III f. 3. 



Fresh water: Kamtschatka (G-run.). 



Var. clnvata Cl. — Broadest at the upper, rounded-truncate end. L. 0,ii; B. 0,03 mm. 



Fresh water: Pitt River, Col. (Grove Coll.)! 



Naviculse Luxuriosae Cl. 



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

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

 narrow space around the median line. Structure: marginal, short strise 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 Diploneis nitc.'iccns. The short marginal striae 

 are apparently smooth, but in a specimen of N. luxnriosa from China I have seen in the marginal 

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



1. N. luxui'iosa Grev. (1862). — V. elliptic-lanceolate, with obtuse, sometimes cuneate, 

 ends. L. 0,o6 to 0,09; B. 0,02.5 to 0,035 mm. Axial area narrow linear, slightly dilated in the 

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

 mentary, sometimes distinctly punctate, striaj. Depressed lateral areas large with 3 to 5 longi- 

 tudinal rows of large pu.ncta straight, or curved towards the median line. — Nav. luxuriosa Grev. 

 T. M. S. XI p. 18 PI. If 10, 11. Nav. lux. var. nmeata Brun. D. esp. n. p. 35 PL XVI f. 3. 



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



2. N. decora Grove and Sturt (1887). — V. elliptical, with obtuse ends. L. 0,o75 to 0,125; 

 B. 0,03 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 strise 7 in 0,oi mm., 

 apparently smooth, slightly radiate. Furrow crossed by faint striaj. 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 PL X f. 13. A. S. Atl. CLXXIV f. 27. 



Marine: Oamaru, New Zealand, fossil! 



3. N. ti'ilineata Grove and Stdrt (1887). — V. elliptic-lanceolate. L. 0,i; B. 0,033 mm. 

 Axial area narrow, slightly dilated towards the middle. Strise 6 in 0,oi mm. crossed by two longi- 

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

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



Marine: Oamaru, New Zealand, fossil! 



Naviculse Nicolbaricse Cl. 



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

 like terminal fissures, bordered on both sides by a longitudinal row of large, sometimes confluent 

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

 strite, radiate throughout. 



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

 to and other species. They have some resemblance to certain Diploneis forms, but the central and 

 terminal nodules are very different. They seem to me provisionally to be nearest akin to Diplon. 

 hiocidata and N. forcipata, although the relation is a distant one. 



