KONGL. SV. VET. AKADEMIENS HANDLINGAR. BAND 27. N:0 3. 131 



The forms comprised in this subgenus agree in all respects, except in the complex nature 

 of the zone, with Psammampkora, for which reason it is impossible to decide whether detached 

 valves belong to one or other of the subgenera. 



Artificial hey. 



^ i Stris on the dorsal side furcate A. spectabilis. Gseg. 



■ I — — — not — 2. 



2 ) Valve reniform A. obesa Cl. a. Geove. 



I 



linear 3, 



., I Valve about 20 times longer than broad A. inflexa BKiB. 



'1 — 6 to 7 — — — — A. ohtusa Gebg. 



1. A. inflexa Bri^b. (1849). — Frustule linear, elongated, with truncate ends. Connecting 

 zone with close and fine divisions. V. arcuate, linear, with rounded ends. L. 0,13; B. 0,oo7 mm. 

 Median line more approximate to the dorsal than to the ventral margin. Central nodule elongated. 

 No areas. Striae 20 in 0,ui mm. parallel, convergent at the ends, where they are closer, very 

 finely punctate. — Amphipleura inflexa Br^b., Kutz Sp. Alg. p. 88. Amphora inflexa H. L. Sm. 

 Lens U p. 78 PL II f. 16 (1873). Okedenia inflexa Eulenst. Ms. Cl. M. D. ^-.o 192 (1879). 

 V. H. T. N:o 167. 



Marine (pelagic): Firth of Tay! Adriatic! 



The fig. in The Lens does not give any idea of the appearance of this isolated and strange 

 form. The complex nature of the zone is very difficult to discover, and I am indebted to Prof. 

 Van Heurck for photographs of specimens, mounted in realgar, which shew it pretty well. 



2. A. obtnsa Greg. (1857). — Frustule in outline elliptic-rectangular, somewhat more than 

 twice as long as broad. V. linear, obliquely rounded. L. 0,o65 to 0,26; B. 0,oi to 0,035 mm. 

 Median line not dilated to a stauros. StriiB 11 to 20 in 0,oi mm. 



Forma typica Cl. — L. of valve 0,075 to 0, 14; B. 0,035 to 0,o5 mm. Dorsal and ventral 

 strise 18 to 20 in 0,oi mm., composed of puncta, 15 to 24 in 0,oi mm. — A. obtusa Greg. T. M. 

 S. V p. 72 PI. I f. 34. A. S. Atl. XL f. 4 to 7, 11 to 13. Amphiprora maxima Eab. Jan. 

 Honduras D. p. 3 PI. II f. 4 (1862), Toxonidea Icevis Witt J. Mus. Godefi'. p. 70 PL VIII f. 9 

 (1873). Amphora permagna Pant. II p. 38 PL VI f. 113 (1889). 



Marine: North Sea! Mediterranean Sea! Adriatic! Black Sea! Red Sea! Seychelles! Mada- 

 gascar! Labuan! Celebes! China! Cape May! North Carolina! West Indies! Campeachy Bay! Mexico! 

 Porto Seguro! Fossil: Hungary, Czekehaza! Oamaru (Strite 17 to 18 in 0,oi mm.). 



Forma minuta Cl. — Frustule 0,063 in length and in breadth 0,o3. B. of the valve 0,03 

 mm. Strise 25 in 0,oi mm.; puncta about 21 in 0,oi mm. 



Marine: Macassar Straits! 



Var. oceanica Castr. (1886). — V. in L. 0,i3 to 0,26; in B. 0,o28 to 0,o3.^ mm. Strise 15 

 in 0,01 mm., composed of puncta, about 15 in 0,oi mm., which form undulating, longitudinal rows. 

 — A. oceanica Castr. Challenger Exp. D. p. 20 PL XXVII f. 20. A. fallax Temp, et Brun D. 

 du Japon p. 14 PL VII f. 13 (1889). A. cyclops Leud. Fortm. D. de Ceylon PL VIII f. 82 (1879)? 



Marine: Gulf of Naples (Deby Coll.)! Ceylon (Le Tourneur Coll.)! Sumatra (V. H. Coll.)! 

 China (Deby Coll.)! Sydney (Castr.), Japan, fossil (Temp. a. Brun). 



Var. Lunyacsehii Pant. (1889). — L. 0,129; B. 0,o28 mm. Stria 9 to 9,5 in 0,oi mm. — 

 A. Lun. Pant. II p. 38; III PL XXXV f. 498. 



Marine: Hungary, fossil (Pant.). 



Var. transfuga Cl. — V. in L. 0,i8 and B. 0,023 mm. Strise 11 to 12 in 0,oi mm.; puncta 

 19 in 0,01 mm. — Amphora ohtusa A. S. Atl. XL f. 16, 17? 



Marine: Madagascar! Macassar Straits! 



