KONGL. SV. VKT. AKADEMIENS I1ANI)LIN(;A1{. HANI:) 27. NK) 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. decussata (Kutz 1859?) Petit (1877). — V. narrow elliptical. L. (),o:i 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. — Kt5TZ Sp. 

 alg. p. 70? Petit He Campb. D. p. 23 PI. 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,o24 mm. Axial area in- 

 distinct; central ai-ea very small, orbicular. Transverse strite 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 80'. — Diatomiste I p. 76 PI. XII f. (5. 



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



Anomoeoneis Pfitrer (1871). 



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

 Structure: small puncta, arranged in transverse, frequently marginal, strire, 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. sphcerophora) 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, 

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



This genus Avas founded by Pfitzer especially for Nar. sph(Brophora and probably for l^av. 

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

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

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

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

 Some of the Navicular, recently described by Pantoksek, seem to be related to A. sphcerophora 

 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. 



Artificial key. 



^ J Valve with rostrate or capitate ends 2. 



' \ — — non- non- — 5. 



j Larger forms. L. (),04 to 0,08 mm 3. 



i .Smaller — L. 0,02 to 0,03 mm 4. 



! Central area rounded, asymmetrical A. sphmrophora Kiixz. 

 — — a transverse fascia A. menilitica Pant. 

 — — dilated to lunate lateral areas A. scnlpta Ehb. 



. ( Valve trachiform A. Follis Ehb. 



\ — lanceolate A. exilis Grun. 



, i Valve linear, slightly biconstricted 6. 



I — lanceolate, not biconstricted 7. 



