KONGL. SV. VET. AKADEMIENS HANDLINGAK. BAND 27. N:0 3. 5 



Fresh water: Finmark! Scotland! Lule Lappmark! Finland, Kuopio! Hungary, Neusiedler- 

 see (Grun.), New Zealand! 



This species seems not to be allied to any other. 



2. N. decnssata (KtiTz 1859?) Petit (1877). — V. narrow elliptical. L. 0,03 to 0,039; 

 B. 0,007 7 mm. Median line ending at a considerable distance from the margin of the valve. 

 Axial and central areas indistinct. Puncta disposed in obliquely decussating rows. — Kutz Sp. 

 alg. p. 70? Petit He Campb. D. p. 23 PL IV f. 11. 



Marine: New Zealand (Pet.). 



I am not acquainted with this species, which in the outline, and the distance between the 

 ends of the median line and the margin, has some resemblance to Navicula Grevillei. 



3. N. Quincunx Cl. (1892). — V. lanceolate. L. 0,o85; B. 0,024 mm. Axial area in- 

 distinct; central area very small, orbicular. Transverse strise 17 in 0,oi mm. almost parallel. 

 Puncta 12 in 0,oi mm., forming oblique rows (14 in 0,oi mm.) crossing each other at an angle of 

 about S0\ — Diatomiste I p. 76 PI. XII f. 6. 



Marine: China (Van Heurck Coll., Deby Coll.)! 



Anomoeoneis Pfitber (1871). 



Valve usually lanceolate, not constricted. Central nodule small. Median line central. 

 Structure: small puncta, arranged in transverse, frequently marginal, strise, and longitudinal, un- 

 dulating or oblique rows. Axial area narrow. Central area unilaterally dilated, or uniting with 

 lateral areas in a lyriform space. Cell-contents (in A. spheerophora) with a single chromatophore- 

 plate, along the inside of one of the walls of the zone and of the valves. The plate has a narrow 

 and deep fissure along the zonal-wall and opposite to the side with the asymmetrical central area, 

 broader sinuses along the ends of the median line and, a sinus below the central area (Pfitzer, 

 Bail u. Entw. p. 78). — In conjugation A. serians is similar to Frustulia (Carter). 



This genus was founded by Pfitzer especially for Nav. spheerophora and probably for Nav. 

 sculpta, principally on the cell-contents. As to Nav. serians Pfitzer hesitates to place it either 

 in this genus or in Neidium. There is no resemblance between Nav. serians and the forms of 

 Neidium, but its structure agrees more with that of A. spheerophora, so it may be placed in the 

 neighbourhood of the latter, although it has not the unilaterally dilated central area of the latter. 

 Some of the Naviculje, recently described by Pantoksek, seem to be related to A. spheerophora 

 and I have included them in Anomoeoneis. 



As this genus is founded principally on the characteristics of the cell-contents, and those 

 of most of the species have not yet been examined, the genus is not well established and re- 

 quires further examination of living specimens. 



'I 



Artificial key. 



Valve with rostrate or capitate ends . . . .2. 



— non- non- — ... . .5. 



J Larger forms. L. 0,04 to 0,08 mm. ... ..... 3. 



\ Smaller — L. 0,02'to 0,o'3 mm. . 4. 



{Central area rounded, asymmetrical . . , . A. spheerophora Kutz. 



. — — it transverse fascia . . . . . . . A. menilitica Pant. 



— — dilated to Innate lateral areas . . A. sculpta Ehb. 



J ( Valve trachiform . . .A. Follis Ehb. 



lanceolate . . .A. exilis Grun. 



' Valve linear, slightly biconstricted . 6. 



lanceolate, not biconstricted .... 7. 



{■ 



