KONGL, SV. VET. AKADEMIENS HANDLINGAR. BAND 27. N:0 3. 137 



Artificial key. 



J (I*. 0,03 to 0,05 mm A. pusilla Cl. 



\l. 0,045 to 0,075 mm. . . 2. 



2 I Central nodnle stauroid . . ... ... . . . A. sendaiana Brun. 



■ I — — not — 3. 



„ ( Valve constricted in the middle . 5. 



■ \ — not — — — 4. 



. f Gestae 8 to 9 in 0,oi mm A. formosa Cl. 



\ — 5 to 6 — — ..... A. Scala Cl. a. Geove. 



{Slightly constricted 6. 

 Strongly — 7. 



Triconstricted , A. dorsalis Cl. a. Geove. 



„ ( Valve with a hyaline wing . . . . .A. limhata Cl. a. Geove. 



I — without — — A. Orovei Cl. 



„ ( Strise 8 in 0,oi mm .A. Camelus Cl. a. Gkove. 



' \ — 10 — — A. biconvexa Jan. 



1. A. pusilla (Greg. 1857?) Cl. — Frustule linear-elliptical, with rounded ends. L. 0,o32 

 to 0,0.53; B. 0,01 to 0,02 mm. V. with obtuse and gibbous ends. Median line biarcuate, at some 

 distance from the ventral margin. Dorsal side striate; strife 12 in 0,oi mm. not distinctly punc- 

 tate. Ventral side not striate. — D. of Clyde p. 525 PL XIV f. 95? Diatomiste 1 p. 159 

 PL XXIII f. 3, 4. 



Marine: Macassar Straits! 



It is doubtful what A. pusilla Greg, may denote. It is described as having coarser strise 

 (9 in 0,01 mm.) than A. bacillaris Greg., to which it otherwise bears a considerable resemblance. 

 There is some doubt about the exact position of this little form, as the ventral side of the valve 

 has, so far as I have hitherto seen, no distinct longitudinal line. 



2. A. Camelus Cl. and Grove (1892). — Frustule of rectangular outline. L. 0,073; B. 0,035 

 mm. Zone with a number of longitudinal divisions (2 in 0,oi mm.) transversely striate; striae 9 

 in 0,01 mm. V. with slightly arcuate median line and the dorsal margin sinuose in the middle. 

 Ends capitate. Dorsal side with 8 striae in 0,oi mm. — Diatomiste I p. 158 PL XXII f. 9 to 12. 



Marine: Macassar Straits! 



3. A. Mconvexa Jan. 1875. — V. with straight ventral margin. Dorsal margin sinuose in 

 the middle, and with rostrate-truncate or capitate ends. L. 0,i to 0,i4; B. 0,oi7 to 0,o25 mm- 

 Median line straight, approximate to the ventral margin. Dorsal strise 9 to 11 in 0,oi mm. alter- 

 nating with single rows of obscure puncta, about 18 in 0,oi mm. Ventral side without striae. — 

 A. S. Atl. XXV f. 68. 



Marine: Macassar Straits (Grove Coll.)! Nossibe (Brun Coll.)! Carpentaria Bay (Atl.). 



This form, of which valves only have been observed, is still imperfectly known, and its 

 place in the system is consequently not well established. The median strise of the dorsal side are 

 often approximate, giving the appearance of a stauros. 



4. A. dorsalis Cl. and Grove (1892). — Frustule rectangular. L. 0,09; B. 0,o3 mm. Zone 

 with a number of longitudinal divisions (about 3 in 0,oi mm.) transversely and coarsely striate; 

 V. with capitate ends and quadri-undulated dorsal margin. Strise 10 in 0,oi mm. — Diatomiste I 

 p. 158 PI. XXII f. 13 to 15. 



Marine: Macassar Straits! 



This species seems to be akin to A. undulata Gkev. (Ed. N. Phil. J. XVII p. 182 f. 3 1863) 

 from Queensland. The latter has however much coarser strise and a not complex zone. 



5. A. limbata Cl. and Grove (1892). — Frustule in outline rectangular, slightly constricted 

 in the middle. L. 0,045 to 0,075; B. 0,02 to 0,035 mm. Zone with several longitudinal divisions 



Kongl. St. Vet. Akad. Haudl. Band 27. N;o 3. 18 



