36 P. T. CLEVE, SYNOPSIS OF THE NAVICULOID DIATOMS. 



6. P. galapageiise Cl. N. Sp. — V. scarcely sigmoid, lanceolate, tapering from the middle 

 to the subaciite ends. L. 0, 17; B. 0,u4f. mm. Median line straiglit, central. Transv. and obl. stria; 

 i'/,4 in 0,01 mm. Angle about 90'. — Pl. IV f. lö. 



Marine: Galapagos Islands! 



This form is nearly akin to P. nicobaricum, but differs by the median striic, wliich are not 

 more distant than the terminal. 



7. P. Eudon Pant. (1886). — V. scarcely sigmoid, lanceolate, tapering from the middle to 

 the snbacute ends. L. 0,28; B. 0,o5 mm. Median line straight, central. Transv. and obl. striae 

 "/,2 (on the fig. in Pant.). Ends of the valve with a lunate marking. — Pant. I p. 30 Pl. XXI 

 f. 190. Per. III f. 21. 



Marine: Hnngary, fossil (Pant.). 



8. P. iiicobcariciim Grun. (18()7). — V. scarcely sigmoid, lanceolate, gradually tapering from 

 the middle to the snbacnte ends. L. 0,14; B. 0,035 to 0, 04 mm. Median line central, straight. 

 Oblique strite more distant in the middle. Transverse stria; coarser than the obliqne (15 to H» in 

 0,01 mm. according to Grcn.). Transv. and obl. strise --'/.^q in 0, 01 mm. (Perag.). Median oblique 

 strise 20, terminal 24 in 0,5 1 mm. (Perag.). — P. validum var.? nicoh. G-run. Novara p. 101 Pl. I. 

 A. f. 20. P. nicohar. Grun. A. D. p. 51. Per. p. 10 Pl. IV f. 9. P. affmc. rar. nicoh. Grcn. in 

 V. H. Syn. Suppl. Pl. C. f. 34. 



Marine: Nankoori, fossil (Grun.), Belgium (V. H.). 



Var. Sagitta Brun. and Tbmp. (1889). — V. rhombic-lanceolate. L. 0, 15 to 0,i7ri; B. 0,o3 

 to 0,030 mm. Median oblique striaj 12 to 14, terminal 17 to 20 in 0, 01 mm. (Brun.). — P Sayifta 

 Brun. and Tbmp. D. foss. du Japon p. 49 Pl. IX I 19. Per. IV f 13. 



Marine: Japan, foss. (Brun.). 



Var. hamnlifera Brun. (1889). — V. rhomboidal. L. 0,09 to 0,12; B. 0,025 to 0, 03 mm. 

 Median line central, straight, curved at the ends. Median oblique strise more distant than the 

 terminal stria; vs^hich are at an aciiter angle. Transv. and obl. strise -'/oi (21 to 24 Brujj) in 0,oi 

 mm. — P. hamuMferum Brun. D. foss. du Japon p. 48 Pl. IX f. 5. Per. p. 13 Pl. V f. 31. P. 

 nicoh. var. indica Per. IV f. 12. 



Marine: Japan (Brun.), China (Deby Coll.)! Sumatra (Per). 



The original P. nicobaricum greatly resembles my P. galapagensc, but according to Gruxow 

 (A. D.) it is nearly akin to P. affine and the fig. in V. H. Syn. evidently represents a form akin 

 to P. Normanii. This is also the case with P. Sagitta Brun. As to P. hamuliferum I have not 

 seen Brun's original specimens, and bis description of the striation is incomplete. In Deby's collec- 

 tion I have seen a specimen closely resembling P. haniuliferum and evidently nearly akin to P. 

 Normanii. It closely resembles /-'. nicoh. var. indica Per. It seems probable that the original F. iiico- 

 haricum may be identical with P. galapagense, and that P. nicoh. Grun. in V. H. Sjni., Per, gra- 

 duates into P Normanii. 



9. P. naviculiiceuni Bréb, (1854). — V. not, or slightly sigmoid, lanceolate, acute. L. O, os 

 0,1; B. 0,015 to 0,02 mm. Median line strongly sigmoid. Median obliqne striie more distant than 

 the terminal, which are at an acuter angle. Transv. and obl. stviss, 'Viei "/ni ""'is- — ^- ^iai'if- Bréb. 

 Mém. de la Soc. du Cherb. 1854 f. 7. Grun. A. D. p. 51. V. H. Syn. Suppl. Pl. C. f. 35. P. 

 transversale W. Sm. B. D. II p. 96 (1856). P japonicum Castr. D. Challenger Ex. XXIX f. 14. 



Marine: North Sea! Mediterranean ! Ceylon! Java! Labuan! 



Forma minuta. L. — 0,o5; B. 0,oi5 mm. Transv. and obl. strise --/jo- 



Marine: Sumatra! Bab el Mandeb.! 



10. P. hniigaricuni Brun. and Cl. (1889). — V. broadly rhomboidal, slightly sigmoid, acute. 

 L. 0,1 to 0,13; B. 0,045 to 0,0B mm. Median line strongly sigmoid. Central nodule orbioular. 

 Median oblique stria; forming a larger angle than the terminal, wliich are more acute. Transv. 



