KONGL. SV. VKT. AKADEMIKNS ITANDLINCAl!. BAM) 27. M:o 3. 105 



blank band across the striae. Striae on the dorsal side 10 to 11 in 0,oi mm. coarsely punctate; 

 puncta about 8 in 0,oi mm., often uniting near the central nodule. — A. libyca Ehb. Ber. 1840 

 p. 11 (fide Kiltz). KtJTZ Bac. p. 107. A. affinis KCtz Bac. p. 107. A. ovalis var. affinis V. H. 

 Syn. p. 59 PL If. 2. A. ovalis A. S. Atl. XXVI f. 102 to 111; PL XXVII f. 4, 5? A. abbre- 

 viata Bleisch Rabh. A. E. 1489 (1863). A. SsontagUi Pant. II p. 39 PL VII f. 138? A. Frotcus 

 var. A. S. Atl. XXVIII f. 1? A. Staubii Pant. HI PL X f. 171 (1893)? A. verrucosa Pant. Ill 

 PL X f. 166 (1893)? A. svavis Pant. Ill PL XXVIII f. 416 (1893)? 



Fresh or brackish water: Spitsbergen (Atl.), Greenland! East Cape! Sweden! England! 

 France! Belgium (V. H.), Germany (Saline Diirrenberg! Konigsberg, foss. !) Hungary fosa. (Pant.)? 



Var. Pediculus KtJTZ (1844). — Frustule in outline broadly elliptical. Valve lunate. L. 0,02 

 to 0,04; B. 0,006 to 0,oo8 mm. Median line slightly biarcuate. Central area distinct and central 

 nodule strong. Striae 14 to 16 in 0,oi mm. coarsely punctate. Ventral side striate. — Cymbella? 

 Pediculus KOtz Bac. p. 80 PL V f. 8. A. ovalis d Pediculus V. H. Syn. p. 59 PL I f. 6. A. ovalis 

 y affinis f. minor {A. Pediculus major Grun.) V. H. Syn. p. 59 PL I f. 4, 5. A. minutissima W. Sm. 

 B. D. p. 20 PL II f. 30 (1853). A. borealis Schum. P. D. I Nachr. p. 23 f. 31 (1863). A. globosa 

 ScHDM. P. D. II Nachr. p. 55 PL I f. 24 (1867). A. sp. n.? A. S. Atl. XXVI f. 102. A. libyca var. 

 interrupta Pant. II p. 37 PL II f. 28. 



Fresh or slightly brackish water, usually attached to larger diatoms, as Nitzschia sigmoidea, 

 or on algse: Sweden! Finland! England! Belgium! Germany! India (Atl.), New Zealand! Tasmania! 

 Hungary, fossil (Pant.). 



Although these varieties are at first sight very dissimilar to each others, they are so inti- 

 mately connected by intermediate forms that I am entirely of the opinion of Grunow and Van 

 Heurck that they should be united. 



13. A. perpusilla Grun. (1880). — Frustule in outline nearly orbicular. L. 0,oo6 to 0,oi; 

 B. 0,004 to 0,005 mm. Valve lunate, with arcuate dorsal, and straight ventral, margin. Central 

 nodule strong. Dorsal striae 16 to 20 in 0,oi mm. almost transverse. Central area usually not 

 distinct. Ventral side without striae. — A. {globulosa var.) perpusilla Grun. V. H. Syn. PL I f. 11. 



A. perp. V. H. Types N:o 4. A. ovalis var. d Pediculus forma minor and exilis V. H. Syn. p. 59 

 PL I f. 8, 9, 10. A. Pediculus A. S, Atl. XXVI f. 99. Cl. M. D. 126, 137. A. globulosa Schum. 

 Preuss. D. II Nachr. p. 55 PL I f. 25. A. S. Atl. XXVI f. 100. 



Fresh water, moist earth etc.: Sweden (Upsala, Dalsland!) Prussia (Schum.), Belgium (V. H.), 

 England, Swansea! France, Meudon! Hungary, Plattensee (Atl.). 



14. A. mexicana A. S. (1875). — V. lunate with arcuate dorsal and straight ventral mar- 

 gin. L. 0,1.5 to 0,20 ; B. 0,03.5 mm. Median line more or less biarcuate. Axial area not distinct; 

 central area small and rounded on the dorsal side. Dorsal side with a longitudinal line more or 

 less approximate to the median line. Striae 6 to 8 in 0,oi mm. coarsely punctate; puncta 6 to 7 

 in 0,01 mm. Ventral side entirely covered with somewhat radiate striae. — A. S. Atl. XXVII 

 f. 47 to 48. Icon. n. PL IV f. 15. A. boryama Pant. Ill PL XXXVIII f. 531 (1893). 



Marine: Morocco! Gulf of Naples! Sumatra (Deby Coll.!), China! Galapagos Islands! Gulf 

 of Mexico (Atl.). 



Var. fusca Ol. — Zone with small irregular puncta giving it a brownish colour. L. 0,i4; 



B. 0,07 5 mm. Striae 8 in 0,oi mm. 



Marine: Macassar Straits! 



I am not quite sure about the identification, as the fig. in Atl. shews a more distant 

 longitudinal line than in my specimens. A. lima A. S. Atl. Probetof. f. 14, which is unknown to 

 me, seems to be allied to A. mexicana. 



15. A. gigantea Grun. (1875). — Frustule broadly elliptical with truncate ends. V. lunate, 

 with straight ventral margin. L. 0,09 to 0,i7; B. 0,025 to 0,035. Median line strongly biarcuate. 



K. Sv. Vet. Akad. Handl. Band 27. N:o 3. 14 



