136 p. T. CLEVE, SYNOPSIS OF THE NAVICULOID DIATOMS. 



Var. incurvata Brun (1891). Valve arcuate. L. 0,i to 0,13; B. 0,oii mm. Striae 6 in 0,oi 

 mm. — A. lanceolata var. incr. Brun D. espfeces n. p. 8 PL XII f. 3. 



Marine: Japan! Western Africa (Brun). 



Var. zelrina A. S. (1875). — V. gibbous in the middle. L. 0,075; B. 0,oo9 mm. Striee 6 

 (dorsal) to 7 (ventral) in 0,oi mm. — A. sebrina A. S. Atl. XXV f. 11. 



Marine: Baltjik Dept. (Atl.). 



2. A. cymbiformis Cl. N. Sp. — V. semilanceolate, acute. L. 0,04 5 to 0,07; B. 0,oo7 to 

 0,013 mm. Axial area indistinct. Striae 14 to 17 in 0,oi mm. — A. S. Atl. PI. XXV f. 9. 



Marine: Port Jackson! Labuan! 



3. A. cymbelloides Grun. (1867). — Hyaline. L. of the frustule 0,o38 to 0,o84; B. of the 

 frustule 0,011 to 0,oi3, of the valve O.oos to O,oii mm. Striae very fine, 29 in 0,oi mm. or more. 

 — Hedw. 1867, VI p. 24. A. angusta var. minitta GtRDN. A. S. Atl. XXVI f. 65, 66. Dannf. 

 Baltic D. PI. I f. 10? A. angusta var. glaherrima Grdn. A. S. Atl. XXVI f. 61, 62. 



Marine: Seychelles! Honduras (Grun.), Barbados! 



The original A. cymbelloides of Grunow is a very delicately striate form, of which the 

 author several years ago sent me a sketch, agreeing with A. angusta var. minuta, or var. glaherrima 

 in A. S. Atl. More coarsely striate forms have since been published as A. cymbelloides (Atl. XXV 

 f. 8, 14) which belong to A. angusta. The var. mauritiana Grun. (Hedwigia 1. c. p. 25) cannot 

 belong to the same species as it has a longitudinal line across the strise. 



4. A. arcta A. S. (1875). — Hyaline. Frustule almost linear with truncate ends. L. 0,094; 

 B. 0,012 mm. Striffi delicate. — Atl. XXVI f. 63. 



Marine: Australia, Port Lincoln (Atl.). 



5. A. magellanica Petit (1888). — V. semilanceolate, acute. L. O.oei to O.oes; B. 0,oi to 

 0,011 mm. Median line straight, approximate to the ventral margin. Axial area indistinct; central 

 small, rounded. Striae 12 in 0,oi mm. finely punctate. — D. de Cape Horn p. 119 PL X f. 14. 

 A. S. Atl. XXV f. 4 (no name). 



Marine: Magellan's Straits! 



6. A. bituniinosa Pant. (1889). — Frustule elongated, elliptical. L. 0,oi6 to0,043; B. 0,012 

 to 0,014 mm. Median line approximate to the ventral margin, slightly biarcuate. Axial and 

 central areas indistinct. Striae 14 to 15 in 0,oi mm. not distinctly punctate and not interrupted 

 or crossed by a longitudinal line. Connecting zone not complex. — Pant. II p. 35 PL I f. 1, 

 PL II f. 23. 



Brackish water: Szardoc, Hungary, fossil! 



It is doubtful whether this species be correctly placed in this subgenus or in the subgenus 

 Amphora, as the median line is not perfectly straight. 



Subgenus Oalamphora Cl. 



Frustule rectangular, with more or less rounded ends. Zone complex, with more or less 

 numerous, transversely striate or costate divisions. Valves linear, obtuse, or with obliquely 

 rounded ends. Median line biarcuate, not closely approximate to the ventral margin. Dorsal side 

 with transverse striae, not crossed by a longitudinal line. Ventral side structureless, but with 

 a longitudinal line. 



This subgenus comprises complex forms, the dorsal striae of which are not crossed by a 

 keel or line. From Halamphora and Oxyamphora they differ by the broader ventral side, which 

 has a longitudinal line, and by the non-protracted or non-rostrate ends. 



