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. 0,i; B. 0,016 mm. Central nodule not dilated into a stauros. Striae 18 in 0,oi mm., punctate; 

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



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



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

 the section Fsammamphora or AmUyamphora. To judge from the fig. in Atl., which represents 

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



2. A. arensu-ia Donk. (1853). — Frustule hyaline, rectangular. L. 0,i to0,i5; B. 0,04 mm. 

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



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

 0,15; B. 0,04 mm. Stria; 27 in 0,oi mm. — A. arenaria Donk. T. M. S. VI p. 31 PI. Ill f. 16. 



A. S. Atl. XL f. 8, 9, 10, 12. V. H. T. N:o 13. H. L. Sm. I N:o 30. 



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



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



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

 PL I f. 13 (1861). A. Donliinii Rabh. F. E. A. p. 96. 



Marine sestuaries: North Sea! Cape May! 



Var. Eattrayi Cl. (1882). — Frustule rectangular, with truncate ends. L. 0,o35 to 0,o4; 

 B. 0,015 to 0,0 17 mm. Striae extremely fine. — A. liattrayi Cl. M. D. N:o 310. 

 Marine: ^Estuaries: Scotland! Belgium! 



3. A. ocellata Donk. (1861). — Frustule rectangular. L. 0,06 to 0,ir; B. 0,028 to 0,o35 

 mm. Valve in breadth 0,05 mm. linear. Central nodule on the dorsal side dilated into a stauros. 

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

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

 towards the median line. 



Var. typica Cl. — L. 0,06 to 0,o9 mm. Striae 21 in 0,oi mm. composed of puncta, about 

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



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



Var. cingulata Cl. (1878). — L. 0,o85 to 0,12; B. 0,oi5 mm. Striae 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,oi3 mm. Striae 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 Hedrck's Coll. from Sumatra has 17 striae and 17 puncta 

 in 0,01 mm. 



Var.? oamaruensis Cl. — V. in L. 0,i8; B. 0,o26 mm. Stauros obscure. Transverse striae 

 16, puncta 14 in 0,oi mm. 



Marine: Oamaru (Grove Coll.)! 



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

 (only 0,0 1 4 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 affinities. 



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

 rounded angles. L. 0,12 to 0,i6; B. 0,o42 mm. V. in breadth about 0,o2 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 Vll f. 8. 



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



