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



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

 minuta of this species. 



57. 0. ovata Grun. (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. Striae 17 in 0,oi 

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

 rows, about 11 in 0,oi mm. — Mast, ovatcu Grun. Verh. 1860 p. 578 PL VII f. 12. A. D. p. 17 

 PL 1 f. 2. Orthon. ov. Grun. Novara p. 98. 



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

 Samoa! Honduras (Grun.). 



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

 B. 0,018 mm. Striae 12 and loculi 4 in 0,oi mm. It is distinguished from 0. ovata principally 

 by the short bands of 7 locnli, which end at a considerable distance from the extremities of 

 the valve. 



58. M. lineata Cl. a. Grove (1891). — V. lanceolate, acute or apiculate. L. 0,093; B. 0,034 

 mm. Loculi 2,5 in 0,oi mm. equal, delicate, with convex interior edges, along the whole margin 

 of the valve. Median line slightly undulate. Central area very small, rounded. Strise 12 in 0,0 1 

 mm. parallel, composed of elongated puncta, forming straight, parallel, longitudinal rows, 7 inO,oi 

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



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



59. M. exarata Cl. N. Sp. — Y. lanceolate, apiculate. L. 0,o65 to 0,o8; B. 0,027 to 0,028 

 mm. Loculi 5 in 0,oi mm. delicate, with straight interior edges forming a narrow band along 

 the margin. No areas. Median line straight. Strise 21 in 0,o 1 mm. parallel, of elongated puncta 

 forming longitudinal, parallel, straight rows, 11 to 12 in 0,oi mm. — PL II f. 35. A. S. Atl. 

 CLXXXVII f. 38. 



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



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



60. M. arata Cl. N. Sp. — V. rhomboid. L. 0,o9 to 0,ii; B. 0,o33 mm. Loculi 3,5 inO,oi 

 mm. delicate, equal, with straight interior edges, forming a band along the whole margin. Central 

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

 sed of elongated puncta, forming straight, parallel longitudinal rows, 11 in 0,oi mm. — PL II f. 9. 



Marine: Island of Rhea, near Singapore! 



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

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

 at a distance from the apices. No areas. Striae about 30 in 0,oi mm., crossed by more distant 

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



Marine: Seychelles (Grun.), Labuan! 



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

 the figure is too little detailed for identification. 



62. M. Ibaltica Grun. (1880). — V. lanceolate, with broad, rostrate ends. L. 0,o3 to 0,04; 

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

 stance from the extremities. Median line straight enclosed between two approximate longitudinal 

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

 — V. H. Syn. PL IV f. 24. M. lanceolata var. elUptica and var. amphicephala Dannf. Baltic D. 

 p. 16 PL I f. 2? 



Brackish water; Baltic (Gothland, Rugen)! South Africa! 



