KONGL. SV. VET. AKADEMIENS HANDLINGAR. BAND 27. N:0 3. 133 



1. A. biggibosa Cl. N. Sp. — V. with two gibbosities on the middle of the dorsal side. 

 L. O, i; B. 0,0 16 mm. Central nodule not dilated into a stauros. Strise 18 in 0,oi mm., punctate; 

 puncta 20 in 0,oi mm. — A. sp. A. S. Atl. XL f. 14. 



Marine: (lulf of Naples (Brun Coll.)! Gulf of Mexico (A. S. Atl.). 



I have not seen entire frustules, so I cannot decide whether this species really belougs to 

 the section Fsanimamphora or Amhlyampltora. To jndge from the tig. in Atl., whieh represents 

 an entire frustule, the zone is not complex, and in sucli case this species is akin to A. areuaria. 



2. A. arenaria Donk. (1853). — Frustule hyaline, rectangular. L. 0,i toO,i5; B. 0,o4 mm. 

 V. linear, with broad ventral side. Strire. very fine, 24 to 27 in 0,oi mm. parallel. 



Forma typica. — Frustule with rounded angles and somewhat gibbous middle. L. 0,i to 

 0,1 ft; B. 0,04 inm. Stri» 27 in 0,oi mm. — A. arenaria Donk. T. M. S. VI p. 31 Pl. III f. 16. 



A. S. Atl. XL f. 8, 9, 10, 12. V. H. T. N:o 18. H. L. Sm. I N:o 30. 



Marine (sestuaries): North Sea! Hungary, fossil (Pant.). 



Var. Donhinii Rabh. (1864). — Frustule elliptic-rectangular to rectangular. L. 0,o7 6 toO,i; 



B. 0,03 to 0,04 mm. StritE 24 to 25 in 0,oi mm. — A. Uneolata Donk. Q. M. J I. N. S. p. 12 

 Pl. I f. 13 (1861). A. Donkinii Rabh. F. E. A. p. 96. 



Marine festuaries: North Sea! Cape May! 



Var. Battrayi Cl. (1882). — Frustule rectangular, with truncate ends. L. 0, 035 to 0,04; 

 B. 0,015 to 0,0 17 mm. Strise extremely fine. — ^-1. liattrayi Cl. M. D. N:o 310. 

 Marine: ^stuaries: Scotland! Belgium! 



3. A. ocellata Donk. (1861). — Frustule rectangular. L. 0,o6 to 0, 11; B. 0,028 to 0,o35 

 mm. Valve in breadth 0,0.5 mm. linear. Central nodule on the dorsal side dilated into a stauros. 

 Terminal fissures small. Striaj 17 to 21 in 0,oi mm. punctate. Ventral side as broad as the 

 dorsal, finely striate. Strite in the middle between the central nodule and the ends divergent 

 towards the median line. 



Var. typica Cl. — L. 0,o6 to 0, 09 mm. StritE 21 in 0, 01 mm. composed of puncta, about 

 24 in 0,01 mm. — A. ocell. Donk. Q. M. J. N. S. I p. 11 Pl. I f. 11. V. H. Syn. p. 56 Pl. I f. 26. 



Marine: Coasts of Sweden! Belgium! England! Adriatic! 



Var. cingulata Cl. (1878). — L. 0,o85 to 0,12; B. 0,oi5 mm. Strite 17 in 0,oi mm.; puncta 

 20 in 0,01 mm. — A. cingulata Cl. D. W. Ind. Arch. p. 9 Pl. III f. 15. A. S. Atl. XXVI f. 17. 

 Icon. n. Pl. III f. 39. 



Marine: Gulf of Mexico! Pensacola! West Indies! N. Carolina! 



Var.? interrupta Pant. (1886). — V. more lunate. L. 0,079; B. 0, 013 mm. Strise 20 in 

 0,01 mm. — A. (ostrearia?) interrupta Pant. I p. 21 Pl. XV f. 134. 



Marine: Hungary, fossil (Pant.). 



As entire frustules have not been seen, it is doubtful whether this form really belongs to 

 A. ocellata. A very similar valve in Van Heurck's Coll. from Sumatra has 17 striee and 17 puncta 

 in 0,01 mm. 



Var.? oamaruensis Cl. — V. in L. 0,i8; B. 0,026 mm. Stauros obscure. Transverse strise 

 16, puncta 14 in 0,oi mm. 



Marine: Oamaru (Grove Coll.)! 



As A. stauropihora Dannfeldt (Baltic D. p. 20 Pl. I f. 9) has described a very small Amphora 

 (only 0,014 mm. in length), which seems to belong to this section, but having had no opportunity 

 of examining it, I am unable to decide about its aifinities. 



4. A. Pleurosigma Tbmp. and Brun (1889). — Frustule thin and flat, rectangular, with 

 rounded angles. L. 0, 12 to 0,i6; B. 0, 042 mm. V. in breadth about 0,02 mm. Ventral side ap- 

 pearently broader than the dorsal. Central nodule dilated to a stauros. Structure, fine puncta 

 disposed in lines crossing each other in the angle of 65°. — D. Foss. du Japon p. 15 Pl. VII f. 8. 



Marine: Japan, fossil (Br. et Temp.). 



