156 P. T. CLEVE, SYNOPSIS OF THE NAVICULOID DI ATOMS. 



Closely akin to M. affirmata in all characteristics, but much smaller. Perhaps a forma 

 minuta of this species. 



57. O. ovata Geun. (1860). — V. elliptical. L. 0,o35 to 0,o36; B. 0,oi8 to 0,o2 mm. Loculi 

 4 to 5 in 0,01 mm. equal, quadrate, forming a rim along the margin. No areas. Strise 17 in 0,oi 

 mm. transverse or slightly radiate at tlie ends, composed of elongated puncta, forming longitudinal 

 rows, about 11 in 0,oi mm. — 3Iast. ovata Grun. Verb. 1860 p. 578 Pl. VII f. 12. A. D. p. 17 

 Pl. I f. 2. Orthon. ov. Grdn. Novara p. 98. 



Marine: Sea of Kära (Grun.), Mediterranean, Adriatic and Black seas! Madagascar! Java! 

 Samoa! Hondnras (Grun.). 



AUied to O. ovata is probably M. ovalis A. S. (Atl. CLXXXV f. 30) from Japan, L. 0,o3; 

 B. 0,018 mm. Strise 12 and loculi 4 in 0,oi mm. It is distinguisbed from O. ovata principally 

 by tbe short bands of 7 loculi, wbicb ond at a considerable distance from tbe extremities of 

 tbe valve. 



58. M. lineata Cl. a. Grove (1891). — V. lanceolate, acute or apicnlate. L. 0, 093; B. 0,o34 

 mm. Loculi 2,5 in 0,oi mm. equal, delicate, witb convex interiör edges, along tbe vrbole margin 

 of tbe valve. Median line sligbtly undulate. Central area very small, rounded. Striee 12 in 0,oi 

 mm. parallel, composed of elongated puncta, forming straigbt, parallel, longitudinal rows, 7 in 0, 01 

 mm. — Diatomiste I p. 59 Pl. IX f. 11. 



Marine: Macassar Straits (Grove Coll.)! Manilla (Deby Coll.)! Cebu! 



59. M. exarata Cl. N. Sp. — V. lanceolate, apiculate. L. 0,o65 to 0,08; B. 0,027 to 0,o28 

 mm. Loculi 5 in 0, 01 mm. delicate, witb straigbt interiör edges forming a narrow band along 

 tbe margin. No areas. Median line straigbt. Striee 21 in 0, 01 mm. parallel, of elongated puncta 

 forming longitudinal, parallel, straigbt rovFS, 11 to 12 in 0,oi mm. — Pl. II f. 35. A. S. Atl. 

 CLXXXVII f. 38. 



Marine: Cbina (Van Heurck Coll.)! Japan (Brun Coll.)! 



Similar to M. lineata, but differs by its closer loculi and finer stiiee. 



60. M. arata Cl. N. Sp. — V. rbomboid. L. 0, 09 to 0, 11; B. 0,033 mm. Loculi 3,, 5 inO,oi 

 mm. delicate, equal, witb straigbt interiör edges, forming a band along tbe wbole margin. Central 

 area moderately large, rounded. Median line undulating. Strise 17 in 0, 01 mm. transverse, compo- 

 sed of elongated puncta, forming straigbt, parallel longitudinal rows, 11 in 0, 01 mm. — Pl. II f. 9. 



Marine: Island of Rbea, near Singapore! 



61. M. acuta Grun. (1883). — V. lanceolate to rbomboid. L. 0,04; B. 0,oi5 mm. Loculi 

 of unequal size, larger in tbe middle, forming a band at some distance from tbe margin and ending 

 at a distance from tbe apices. No areas. Strise about 30 in 0, 01 mm., crossed by more distaut 

 longitudinal furrows, about 17 in 0,oi mm. — Vega p. 494 Pl. XXXV f. 8. Icon. n. Pl. II f 13. 



Marine: Seycbelles (Grun.), Labuan! 



M. lineolata A. S. (Atl. CLXXXVI f. 33) from Malabar resembles somewbat M. acuta, but 

 tbe figure is too little detailed for Identification. 



62. M. baltica Grdn. (1880). — V. lanceolate, witb broad, rostrate ends. L. 0,03 to 0,04; 

 B. 0,013 to 0,016 mm. Loculi 6 in 0, 01 mm. equal, quadrate, forming a band, ending at some di- 

 stance from tbe extremities. Median line straigbt enclosed between two approximate longitudinal 

 ribs. No areas. StritB 20 to 21 in 0,oi mm. finely punctate; puncta forming longitudinal rows. 

 — V. H. Syn. Pl. IV f. 24. M. lanceolata var. elliptica and var. amphicephala Dannp. Baltic D. 

 p. 16 Pl. I f. 2? 



Bracki.sh water: Baltic (Gothland, iiiigen)! South Africa! 



