190 P. X. CLEVE, SYNOPSIS OF THE NAVICULOID DIATOMS. 



9. A. trinodis Arnott (1861). — Linear, gibbons in the middle and at the broad ends. 

 L. 0,015 to 0,02; B. 0,0 5 mm. Upper V. witli narrow axial area dilated in tlie middle to an 

 almost orbicular, small central area. Strite abont 30 in 0, 01 mm. parallel. Lower V. withont 

 distinct axial area and with small central area. Striae abont 30 in 0,oi mm. parallel. — Aclman- 

 thiclium. trinode Pritch. Inf. p. 872 Pl. VIII f. 9. Nav. trinodis Grun. Verli. 1860 p. 551 Pl. IV 

 f. 8. Ehoiconeis trin. Grun. Verli. 1863 p. 147. Aclm. trin. V. H. Syn. Pl. XXVII f. 50 to 52. 



Fresh water: England, Tyrol (Grnin.). 



10. A. deliciitula Kdtz. (1844). — Elliptic-lauceolate, frequently with subrostrate ends. 

 L. 0,01 to 0,02; B. 0,005 to 0,0 11 mm. Upper V. witli narrow, linear axial area. Strise 14 to 15 

 in 0,01 mm. almost parallel. Lower V. with indistinct axial area and very small, orbicular central 

 area. Strite 17 to 19 in 0, 01 mm. the median shorter. — Achnanthidium delicatidum KtJTZ. Bac. 

 p. 75 Pl. III f. 21. Achnanthes delic. Grun. A. D. p. 22, 1880. V. H. Syn. p. 130 Pl. XXVII f. 3, 4. 



Brackisli water: Greenland! Arctic America! North Sea! English Channel! Balearic Islands! 

 San Francisco! 



11. A. Hanckiana Grun. (1880). — Elliptical to elliptic-lanceolate. L. 0,012 to 0,03i; 

 B. 0,006 to 0,008 mm. Upper V. with linear, narrow axial area. StritB 10 to 12 in 0,oi mm., 

 parallel, lower V. without axial area and with small central area. Strise 10 to 13 in 0, 01 mm. 

 radiate. — A. D. p. 21. AcJm. Hauchii Grun. V. H. Syn. Pl. XXVII f. 14, 15. 



Hot springs and brackish water: Triest (Grun.), Canada! New Zealand! Tasmania! Cape Horn! 



12. A. afiKnis Grun. (1880). — Linear-lanceolate, obtuse. L. 0,oi5 to 0,023; B. 0, 003 to 

 0,0035 mm. Upper V. with narrow, linear axial area. Strise parallel 27 to 30 in 0, 01 mm. Lower 

 V. with narrow axial area. Central area a transverse fascia, reaching to the margin. Strise about 

 30 in 0,01 mm. radiate throughout. — A. D. p. 20. V. H. Syn. p. 130 Pl. XXVII f. 39, 40. 



Fresh water: Belgiuni (V. H.), Tasmania! North America, White Mountains! 

 Var. jamalinensis Grun. (1880). — L. 0,037; B. 0,oo5 mm. Strife of the lower V. 16 in 0, 01 

 mm. — A. hungarica var.? jamal. Grun. A. D. p. 20. 

 Marine (?) : Sea of Kära (Grun.). 



13. A. exigua Grun. (1880). — Broadly elliptic-lanceolate, with rostrate, obtuse ends. 

 L. 0,013 to 0,017; B. 0,005 to 0,006 mm. Upper V. with narrow, linear axial area. Strise about 

 22 in 0,01 mm. parallel. Lower V. with very narrow axial area. Central area a transverse 

 fascia, reaching to the margin. Strise about 25 in O, o 1 mm. slightly radiate throughout. — Stanro- 

 neis exilis KtJTZ. Bac. p. 105 Pl. XXX f. 21. Schum. Preuss. D. II Nachtr. Pl. II f. 59. Ach. 

 exlyua Grun. A. D. p. 21. V. H. Syn. Pl. XXVII f. 29, 30. 



Fresh water, hot springs: Sweden (Hernösand, interglacial deposit)! Germany (Berlin)! 

 Brazil! Ecuador! Surinam! Java! New Zealand! Hawaii! 



14. A. hungarica Grun. (1863). — Narrow elliptical or linear-lanceolate with subcuneate 

 ends. L. 0,02 to 0,03; B. 0,oo6 to 0,oo7 mm. Upper V. with narrow axial area, in the middle 

 dilated to a narrow, short, transverse central area. Striae about 21 in 0, 01 mm., parallel. Lower 

 V. with narrow axial area. Central area a broad fascia. Strise about 21 in 0, 01 mm., slightly 

 radiate. — Achnanthidium hungaricum Grun. Verh. 1863 p. 146 Pl. IV f. 8. Achnanthes Ining. 

 A. D. p. 20. V. H. Syn. p. 130 Pl. XXVII f. 1, 2. Achnanthidinm ncglcctum ScuuM. Preuss. 

 D. II Nachtr. p. 54 Pl. I f. 17? 



Fresh water: Sweden (Grun.), Belgium (V. H.), Hungary (Grun.), Illinois! Brazil! Ecuador! 

 Australian Alps (Rieva l^agoon)! 



To tliis group niay l)elong Achnanthes Gregoryana Grev. (M. J. VII p. 84 Pl. VI f. 13, 14) 

 if this form, of which the zonal vicw is figured, be really an Achnanthes, but it appears more 

 probable that it may represent an arcuate Gyrosigma perhaps G. arcticuni. 



