KONGL. SV. VET. AKADEMIENS HANDLINGAE. BAND. 26. N:0 2. 



1. Nitzchiese 



2. Amphiprora 



3. Pleiirosigma 



4. Tropidonels < 



5. NaviculsB fu- 



siformes 



6. Prustnlia 



7. Navieulae mi- 

 crostigmaticBB 



8. Naviculffi de- 

 cipientes 



Amphiprora (S) Auricula. 

 Tropidoneis (4). 



. . . . Dictyoneis , . Mastoneis. 

 . . . . Seoliotropis .... Gomphoneis. 

 . . . . Pleurosigma (S), Toxonidea. 

 .... Navicnlse Decussate . . .- Anomoeoneis. 

 NaviculiB fusiformes (5). 

 Naviculse micrnstigmaticse (7). 

 Naviculse othostichse. 

 Gyrosigma. 

 Frustulia (6). 

 Cistula. 

 Stenoueis. 

 Amphipleura. 

 Brebissonia. 



Nav. minusouIsB .... Microneis. 

 Nav. decipientes (8). 

 Nev. punctatae (9). 

 Anorthoneis. 

 Eucocconeis. 

 Halamphora. 

 Oxyamphora. 

 Amblyamphora. 

 Psammamphora. 

 Nav. bacillares. 

 Nav. entoleise. 

 Nav. mesoleiae. 

 i . . . . Heteroneis. 



Nav. lineolatae (10). 



Nav. lyratEB (12). 



Nav. heterostichae .... Actinoneis. 



.... Achnanthidium. 



.... Disconeis. 



ICymbella. 

 Gomphonema, Rboicosphenia. 

 Trachyneis. 

 Nav. IsevistriatsB (11). 

 f Pinnularia. 

 ■! Cymbamphora. 

 [ Arcbaeampbora. 

 i Diploneis (13). 

 \ Pseudo-amphiprora (14). 

 Amphora . . Diplamphora. 

 Cymatoneis. 

 Scoliopleura. 

 Nav. nicobaricae. 

 Nav. luxuriosEE. 

 j Caloneis .... Neidium. 

 \ . . . . Calamphora. 



Achnanthes .... Pleuroneis. 

 Mastogloia. 

 f Cocconeis. 

 \ Campyloneis. 



{: 



Tropidoneis comprises both symmetrical not-winged and asymmetrical winged forms. The 

 former appear to be related to the Navieulce microstigtnaticce a,nd Nav. fusiformes. As asymmetrical 

 forms of the Nav. microstigmatica are to be considered the following sections of the old genus Amphora: 

 Oxyamphora, Amhly amphora, Psammamphora probably also Halamphora. Anorthoneis is probably 

 an asymmetrical form of Nav. microstigmaticce. The Nav. minusculoe, of which Microneis and 

 Eucoceoneis appear to comprise degenerating forms, are probably also allies of Nav. microstigmaticce _ 

 To the last named large section the Nav. decipientes, Nav. entoleice and Nav. mesoleice are certainly 

 akin. Heteroneis may comprise degenerating forms allied to the same group. 



From the Nav. microstigmaticce the passage is gradual to the Nav.punctatce and Nav. heterostichce 

 and the former section is very closely connected with the Nav. lyratce. As degenerating forms are 

 perhaps to be regarded Disconeis and Achnanthidium. Also some asymmetrical forms exist in 

 the section Nav. punctatce. Some CymiellcB represent very likely asymmetrical forms of Nav. 

 punctatae. 



The Naviculce Lyratce are by intermediate forms connected with Diploneis. Akin to the 

 Nav. lyratce I also consider Pseudo-amphiprora. The new groups Amphora and Diplamphora, 

 broken out from the old genus Amphora, may be regarded as asymmetrical forms of Diploneis. 



Pseudo-amphiprora is connected by intermediate forms with Caloneis, to which also Neidium 

 seems to be allied. 



The Nav. lineolatce pass over to the group Punctatce by transitional forms, and the former 

 are also akin to Trachyneis (with the asymmetrical form Amphora Clevei). A part of the Cymbellce, 

 Gomphonema, Ehoicosphenia and Amphora lahuensis may be considered as asymmetrical forms of 

 the Nav. lineolatce. Degenerated forms of the Nav. lineolatce are probably to be found in Actinoneis. 

 — On the other hand the Nav. lineolatce are closely connected with the Nar. Icevistriatce, and those 

 with Pinnularia, and I consider, with much hesitation, Cymbamphora as asymmetrical forms of the 

 Nav. Icevistriatce. 



Kongl. Sv. Vet. Akad. Handl. Band 26. N:o 2. 2 



