26 p. T, CLEVE, SYNOPSIS OE THE NAVICULOID DIATOMS. " 



Marine: Grreenland! Spitsbergen! Finmark! Sea of Kara! Cape DeschnefF! Behrings Island! 

 Japan, fossil! Paeiiic Ocean (Grrun.). 



N. Bolleana has somewhat dissimilar valves, the concave having more strongly radiate striie 

 than the convex. Original specimens of Nar. Index Temp. a. Brun are perfectly similar to 

 specimens of N. Bolleana, determined by (tRUNOW. 



45. N. incerta (tRUN. (IMKO). ^ V. linear, with slightty convex margins and obtuse ends. 

 L. 0.0 1.^); B. (),()()(; mm. Axial and central areas indistinct. Striae If) in 0,01 mm., scarcely radiate. 

 - V. H. Syn. p. 107 PI. XIV f. 43. 



Marine: Belgium (V. H.). 



A small form, remarkable for its coarse stride, unknown to the author. Its place in the 

 system is doubtful. 



40. N. (Schizoneiua) corymbosa C Ag. (1824). V. narrow, lanceolate, obtuse. L. 0.01; 

 B. 0,()()2 mm. Axial and central areas indistinct. Strise 23 in 0,()i mm. very slightly radiate. — 

 ScMzoncma coripnhosum Ka. Syst. Alg. p. 11. V. H. Syn. PI. XVI f. 21. 



Marine: Japan (Grun.). 



The frustules live in hair-fine branched tubes . 



47. N. (Schizouenia) mollis W. Sm. (185G). — V. lanceolate, obtuse. L. 0,027 to 0,i):!2; 

 B. 0,006 to 0,007 mm. Axial and central areas indistinct. Strife 14 to Ifi in 0,0 1 mm. radiate in 

 the middle, el.sewhere parallel, finely lineate; lineola^, forming longitudinal striae. — SrJiiznii. niollc 

 W. Sm. B. D. II p. 77 PI. LVIII f. 3fio. V. H. Syn. PI. XV f. ii, 23. S. nlhiccrm V. H. Syn. 

 1. c. f. 20. S. torr/natum V. H. Syn. 1. c. f. 21. 



Marine: Arctic Amercia, Cape Sabine! Bohuslan! North Sea! Adriatic! 



The frusti;les are crowded in very branclied. soft tubes, forming branches 15 to 30 crat. long . 



A form intermediate between N. niollis and A. rumosissima is S. setaeeum V. H. Syn. XV 

 f. 13. The frustules of this form live crowded in stiff, olive-green coloured, arborescent and very 

 branched tubes. 



48. N. (Schizonenia) nirtiilans Cl. (1892). — V. narrow linear-lanceolate. L. 0,026; B. 0,oo.^) 

 mm. Axial and central areas indistinct. Striae 22 in 0,oi mm., parallel. Frustules inhabit the 

 interior of marine algte. — Cl. Diatomiste I p. 78 PI. XII f. 12. 



Marine: South coast of Australia, iu the thallus of a Chylocladia, sent by Prof. J. Agardh ! 



49. N. (Scliizoneina) ramosissima Ao. (1824). — V. linear-lanceolate, with obtuse ends. 

 L. 0,0.5 1 to 0,072; B. 0,01 to 0,008 ram. Axial and central areas indistinct. Striae 12 to 13 in 

 0,01 mm. parallel, finely lineate, lineolae forming longitudinal striae, about 30 in 0,oi mm. 



Forma caspia (tRUN. (1878). — L. O.o.'is to 0,o.'j2; B. 0,oo7 to 0,oo8 mm. Striaj 12 in 0,oi 

 mm. — Casp. Sea Alg. p. 19 PL IV f. 21. 



Brackish water: Caspian Sea (Grun.). 



Forma genuina Cl. — L. about O.o.'^i mm. — Schiz. ram. C. A. Syst. Alg. p. 11. V. H. 

 Syn. p. 110 PI. XV f. 4, 5. 



Marine: North Sea! 



Forma uniplia Grun. (1880). — L. 0,o6 to 0,072; B. 0,007 to 0,oo8 mm. Strite 10 to 12 in 

 0,01 mm. - Schizon. amplius Y . H. Syn. PI. XV f. 3. — A. S. N. S. D. Ill f. .5. 



Marine: North Sea! Canada! Mauritius! 



N. ramo.Hssima lives enclosed in gelatinous tubes on the various forms of which a great 

 number of species and varieties has been founded (see Grunow's paper in Botan. (^entralbl. 1880). 

 As mentioned above, this species is near-ly akin to N. mollis, and on the other hand to smaller 

 forms of A. (lircrtd r/ir. suhfilis, from whicli A. raniosissivin can scarcely be distinguished. 



