186 V. T. CLEVE, SYNOPSIS OF THE NAVICULOllJ DIATOMS. 



Var. inciirruta Brun (1801). Valve arcuate. L. 0, i to (),i3; B. 0,on mm. Strite 6 in 0,01 

 mm. — ■ A. lanceolata var. incr. Brun D. espeees n. p. 8 PI. XII f. n. 



Marine: Japan! Western Africa (Brun). 



Var. s:ebrina A. S. (1875). — V. gibbous in the middle. L. 0,o7r); B. O.oo'.t mm. Stria' G 

 (dor.sal) to 7 (ventral) in 0,oi mm. — A. schrina A. S. Atl. XXV f. 11. 



Marine: Baltjik Dept. (Atl.). 



2. A. cymbifonnis Cl. N. Sp. — V. semilanceolate, acute. L. 0,045 to 0,07; B. (),()07 to 

 0,0 1,3 mm. Axial area indistinct. Stria? 14 to 17 in ().(ti mm. — A. S. Atl. PI. XXV f. !). 



Marine: Port Jackson! Labuan! 



3. A. cymbelloides Grun. (1867). — Hyaline. L. of the frustule (),038 to 0,o84; B. of the 

 frnstule O,oii to (),oi.s, of the valve O.oos to 0,on mm. Stria? very fine, 29 in 0,oi mm. or more. 

 — Hedw. 1867, VI p. 24. A. angtisfa var. mimda Grun. A. S. Atl. XXVI f. 65, 66. Dannf. 

 Baltic D. PI. I f. 10? A. angx.sta var. f/lahcrrhiia Grun. A. S. Atl. XXVI f. 61, {V2. 



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



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

 author several years ago sent me a sketch, agreeing with A. aiif/iisfa vur. mi tin fa, or rar. (iluhcrrima 

 in A. S. Atl. More coarsely striate forms have since been published as A. ci/mhelloidcs (At). XXV 

 f. 8, 14) which belong to A. angnsta. The var. mauritiana Grun. (Hedwigia 1. c. p. 2,5) cannot 

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



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

 B. 0,0 12 mm. Stria? delicate. — Atl. XXVI f. 63. 



Marine: Australia, Port Lincoln (Atl.). 



5. A. magellanica Petit (1888). — V. semilanceolate, acute. L. O.ooi to 0,or,3; B. 0,0 1 to 

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

 small, rounded. StriiB 12 in 0,oi mm. finely punctate. — I), de Cape Horn p. 119 PI. X f. 14. 

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



Marine: Magellan's Straits! 



6. A. bitinuinosa Pant. (1889). — Frustule elongated, elliptical. L. 0,oio to 0,04.3; B. 0,012 

 to 0,0 14 mm. Median line approximate to the ventral margin, slightly biarcuate. Axial and 

 central areas indistinct. Stria' 14 to If) in 0,oi mm. not distinctly punctate and not interrupted 

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

 PI. 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 Calamphora 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 witli obliquely 

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

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

 a b)ngitudinal line. 



This sul)genus comprises complex forms, the dorsal stria' of which are not cro.ssed by a 

 keel or line. From IIuUoHphora and Oxyainpliora they diffei- l)y the broader ventral side, which 

 has a bmgitudinal line, and by the u(m-pr«>tract»^d nr iKiii-nistrate ends. 



