KONGL. sv. vpyr. akademiens handlingar. band 27. n:() 3. 37 



Var. schizostauron Cl. — L. 0,038; B. 0,o2 mm. Strise 7 in 0,01 mm. Lineolfe 20 in 0,oi 

 mm. Central nodule lyriformly dilated. 

 Marine: China (Thum.)! 



103. N. Chi Cl. N. Sp. — V. broad, constricted in the middle, with apieulate ends. L. 0,o5; 

 B. 0,027, at the constriction 0,o2i mm. Central pores approximate, terminal nodules near the ends. 

 Axial and central areas uniting in a large space, crossed by faint continuations of the strise. 

 Strise 9 (middle) to 12 (ends) in 0,oi mm. radiate in the middle, transverse at the ends, very 

 finely lineate. — PI. I f. 29. 



Marine: Balearic Islands! Grulf of Naples! 



This form may easily be mistaken for iV^. Exul, but it has no axial band of striee. Besides, 

 the strise are very finely lineate. 



Additional. 



104. N. Aquitaniae Brun a. H^rib. (1893). — V. narrow elliptic-lanceolate, with obtuse 

 ends. L. 0,i- to 0,24; B. 0,034 to 0,045 mm. Axial area in width about a third of the breadth 

 of the valve, lanceolate, slightly dilated in the middle. Strise 10 in 0,oi mm. slightly radiate in 

 the middle, where some few are shorter than the others, convergent and genuflexed in the ends, 

 punctate; puncta about 16 in 0,oi mm. — D. d'Auvergne p. 81 PI. II f. 4. 



Brackish water: Auvergne, fossil! 



A very remarkable species, the terminal strise of which are genuflexed as in N. ohlonga. 

 Varies with undulating margins (var. undulata Brun). At the inner ends of the strise there is a 

 narrow blank band or depression. 



105. N. basaltae proxinia Brun a. H:6rib. (1893). — V. linear, with cuneate ends and 

 parallel or .slightly concave margins. L. 0,o7 5 to 0,o9; B. 0,oi4 to 0,oi8 mm. Axial area narrow, 

 dilated to a large central area. Strise 10 in 0,oi mm., radiate in the middle, convergent in the 

 ends, finely punctate. — D. d'Auvergne p. 89 PL II f. 5. 



Brackish water: Auvergne, fossil! 



Naviculse Punctatse. 



Valve usually symmetrical, elliptical to lanceolate, with broad and rounded or, frequently, 

 rostrate ends, rarely constricted in the middle, or with undulate margins. Median line usually 

 central; central nodule not stauroid or dilated in lyriform processes; terminal fissures turned in 

 the same or, sometimes, in contrary, directions. Axial area narrow or indistinct. Central area 

 usually small, rarely transverse, and never dilated to a transverse fascia. Structure: distinct 

 puncta arranged in transverse rows (strise) radiate at the ends and in the middle of equal or 

 unequal length, and, besides in longitudinal, undulating, rarely straight, rows. No longitudinal 

 lines or lateral areas (except in N. carinifera and N. interlineata). Connecting zone not complex, 

 usually narrow. Cell-contents unknown. 



This section, characterized by the distinct puncta composing the strise, comprises two, not 

 sharply distinct, divisions • — forms with the median strise of equal length, and forms with the median 

 strise alternately longer and shorter. The former division is very neai'ly akin to the Lyratse, 

 which differ in the lateral areas. In many forms of the Punctatse there is a tendency to form 

 lateral depressions or areas, where the puncta are less crowded, which suggests a passage to such 

 forms of Lyrat{;e as N. irrorata, N. fluitans and others. Some forms are distinctly intermediate 

 between the two sections, as N. carinifera. 



