KONGL. SV. VET. AKADEMIENS HANDLINGAK. BAND 27. N:0 3. 85 



longer and shorter^ very convergent at the ends. — Am. p. 133. M. Gr. U: 2 f. 13. Nav. Sill. 

 Lewis Proceed. Acad. Nat. Scienc. Philad. PI. II f. 8. Walker a. Chase N. a. R. D. PI. 11 p 6 

 PL II f. 2. 



Fresh water: North America, Crane Pond! New Hampshire (Ehb.), Wolfboro (Lewis). 



39. P. lignitica Cl. N. Sp. — V. lanceolate, with protracted, broad and rounded ends. 

 L. 0,075; B. 0,019 mm. Terminal nodules hook-shaped. Axial area uniting with the central 

 area in a lanceolate space. Striae 13 in 0,oi mm., slightly radiate, at the ends convergent. — 

 PI. I f. 15. 



Fresh water: Japan, lignite (Brun Coll.)! 



Nav. transylvanica Pant. (Ill PI. I f. 7) and its var. producta (1. c. PI. XXm f. 345) 

 may be akin to this species, if they do not represent a Caloneis allied to C. formosa, which I am 

 unable to decide from the figures. 



40. P. Thorax Brun (1891). — V. lanceolate, with more or less protracted, obtuse ends. 

 L. 0,04 to 0,0065; B. 0,oi7 to 0,02 mm. Terminal fissures small and indistinct. Axial and central 

 areas uniting in a lanceolate space. Strise 6 in 0,o) mm., slightly radiate, convergent, and closer 

 near the ends. — Nav. Thorax Brdn D. espfeces n. p. 41 PL XVI f. 6. 



Fresh water: Japan, lignite (Brun Coll.)! 



VI. Brevistriatse. 



Artificial hey. 

 ^ f Margins of the valve undnlate .... . .... N. nodosa Ehb. 



■ I — — — not — 2. 



Area punctate N. acrosphwria Bb^b. 



— not — 3. 



Ends cuneate 4. 



not — 5. 



. I Median line straight P. singularis A. S. 



I — — flexnose P. integra Gkun. 



Linear lanceolate, tapering from the middle 6. 



^1 



{ 



„ I Striae 10 to 11 in 0,oi mm P. parva Ehb. 



' \ — SI to 22 — — P. modesta Grun. 



- ( Strise 8 to 10 in 0,oi mm 8. 



I — 14 to 15 — ~ P. paulensis Grun. 



L. 0,1 to 0,12 mm P. brevieostata Cl. 



L. 0,05 to 0,08 mm P. hemiptera Kutz. 



{; 



41. P. hemiptera Kutz (1844). — V. elliptic-linear to linear, narrowed towards the often 

 subcuneate ends. L. 0,05 to 0,08; B. 0,oi2 to 0,oi3 mm. Axial area generally wide, more or less 

 lanceolate. Terminal fissures semicircular. Strise 8 to 10 in 0,oi mm. slightly radiate or almost 

 parallel. — Nav. hem. Kutz Bac. p. 97 PL XXX f. 11. A. S. Atl. XLIII f. 28, XLV f. 9. P. 

 acuminata W. Sm. B. D. XVIII f. 164. Sav. instaUlis A. S. Atl. XLIII f. 35 to 40. Nav. de- 

 hilis Pant. II p. 44 PL XII f. 214 (1889). Nav. hyhrida B.t&iB. a. Perag. D. d'Auvergne p. 85 

 PL IV f. 9 (1893). Nav. hyhrida var. BielawsMi HfeiB. a. Perag. 1. c. p. 85 PL IV f. 10. 



Fresh water: Sweden (Lapland to Skane)! Finland (Russian Lapland to Abo)! Norway! 

 Iceland! Great Britain (Premnay Peat, Loch Kinnord)! Italy (S:ta Flora Dept.)! Hongkong (Atl.), 

 New Zealand! Australia (Blue Mountains)! America (Waltham Mass., Crane Pond, Demerara River, 

 Brazil, Trinidad)! 



Var. interrupta Cl. — Strise uni- or bilaterally interrupted in the middle by a trans- 

 verse fascia. 



Fresh water; Japan, lignite (Brun Coll.)! 



