KONGL. SV. VKT. AKADEMIENS HANDLINGAR. 



BAND. 



27. 



n:o 



117 



32. A. marf^'.iritifera Cl. N. Sp. — Frustule iiidfuted in the middle, bicuneate, with broad, 

 truncate ends. L. (),o2 7 to 0,04; B. 0,nir> mm. Zone with about 4 division.s in 0,oi mm. coarsely 

 transversely striate. Striae '"^ in '>,()i mm., composed of distinct puncta. V. with arcuate dorsal, 

 slightly convex ventral margin, and rostrate ends. L. (),().-!r); B. 0,oi mm. Median line straight. 

 Longitudinal line indistinct. Central nodule not stauroid. Axial area indistinct; central small 

 rounded. Dorsal strife 8 in 0,oi mm., composed of a few large puncta, crossed by a broad, blank 

 area. Ventral side with a row of small puncta along the margin (10 to 11 in 0,oi mm.). — 

 PI. Ill f. 30, 31. 



Marine: Galapagos Islands! 



Subgenus Halamphora Cl. 



Frustule elongated, sometimes constricted in the middle. Connecting zone complex. Valve 

 boat-shaped, usually with rostrate or capitate ends. Median line close to the ventral margin. 

 Axial area usually indistinct. No longitudinal line on the dorsal or ventral side. Structure: 

 puncta disposed in transverse strife. 



This subgenus, to which belongs A. salina of W. Smith, comprises a large number of 

 forms, closely connected in part. They differ from Cymhamphora by the zone being complex, by 

 the, usually, capitate ends and the distinctly punctate strife. The small terrestrial A. Normani 

 seems to be related to A. perpnsilla of the subgenus Aviphora, so also A. veneta and ^4. commu- 

 tata, otherwise there is no close connection between this and any other group of Amphora. 



2. 

 3. 

 4. 



5. 



6. 



7. 



8. 



9. 

 10. 

 11. 

 12. 

 13. 

 14. 



Artificial key. 



( Striae crossed by a longitudinal band A. intersecta A. S. 



■! — — by several — blank lines A. czekehazensis Pant. 



I — not — — — 2. 



j Striae with distant puncta 3. 



I — closely punctate 4. 



j Dorsal margin slightly triundulate A. Grunowii A. S. 



I — — not undulate A. corpulenta Cl. a. Grove. 



) Valve constricted 5. 



i — not — 11. 



j Valve with one constriction 6. 



J — — two constrictions A. Jeschkei Jan. 



I — — several — 10. 



j Zone on the dorsal side reticulate A. Prragalli Cl. 



I — — — — not — 7. 



j Constriction with a median gibbosity A. bullata Cl. 



\ — without — — 8. 



j Divisions of the zone faint A. bigibba Gbdn. 



\ — — — distinct 9. 



j Dorsal striae about 13 in 0,oi mm A. trinodis Greg. 



1 — — 9 to 10 — — A. angularis Greg. 



( Undulations equal A. tcfragihba Cl. 



\ Median undulation larger than the others A. sarniensis Grev. 



( Striae 5 in 0,oi mm A. clara A. S. 



\ — 9 to 10 in 0,01 mm 12. 



j Ends of the valve not capitate 13. 



I ^ — — capitate, not curved inwards 18. 



j Ends not rostrate 14. 



1 — • rostrate, curved inwards 16. 



j Striae 20 in 0,oi mm A. veneta KtJTZ. 



I — 12 to 14 in 0,01 mm 15. 



