OP THE FEAGILAEIEJE. 



77 



pucina, SBD. pi. 35. f. 296. Europe, 

 Asia, Africa, and America. 1-1152" j 

 six times longer than broad. 



F. corriKjata (K.). — Minute ; frustules 

 geminate, corrugated at each end ; valves 

 acutely lanceolate. KB, p. 45, t. 16. f. 5. 

 Germany. 1-1440". 



F. pusilla (K.). — Glassy ; frustules 

 rectangular, quadrate, or linear, united | 

 in very short fascias ; valves naiTow 

 linear, " smooth. KSA. p. 14. Marine. 

 France. 



F. Bacillum (E.). — Valves smooth, 

 linear wdtli roimded ends, five or six 

 times as long as broad. EB. 1844 ; 

 Microg. pi. 21. f. 30 & pi. 35.^16. f. 11. 

 Fossil. Oran and Virginia. 1-720". 



F. glabra (E.). — Linear, smooth, with 

 attenuated obtuse apices. EA. p. 127. 

 Guiana. May be a variety of F. bi- 

 ceps, E. 



F. Catena (E.). — Twice as long as 

 broad ; valves oblong, smooth. EB. 

 1840, p. 16. = F. tw-gens, EM. several 

 figures ? Europe, Africa, and Mexico. 

 1-1152". 



F. virescens (Ralfs). — Valves turgid 

 lanceolate, suddenly contracted towards 

 the obtuse ends ; striae 44 in -001", verv 

 faint. Ralfs, Ann. xii. ; SBD. ii. p. 22, 

 pi. 35. f. 2d7. = Diatoma virescens, HBA. 

 F. pectinalis, E. Streams. Europe. Fila- 

 ments elongated, lurid-green ; frustules 

 rather broad, with distinct terminal 

 puncta, frequently irregularly adhering 

 by their angles like a Diatom. Easily 

 recognized by its greenish hue when 

 growing. 



F. Venter (EM. several figures). — 

 Minute ; valves smooth, t^dce as long- 

 as broad, oblong lanceolate, with con- 

 tracted, produced, obtuse ends. 



F. mesotyla (E.). — Bacillar with tur- 

 gid centre, obtuse ends, and transverse 

 granular striee. Asia. 1-480". Resembles 

 Stauroneis granulata, but wants the lon- 

 gitudinal band and crucial umbilicus, E. 



F. Jcevis (E.). — Resembles Oclontidium 

 amphiceros, but is without the dotted 

 striae. EA. p. 127. Virginia. 



F. bicejys (E.). — Valves linear oblong, 

 suddenly constricted at the ends into 

 minute beaks ; strias wanting or obscure. 

 EA. p. 127; Microg. several figures. 



z=F. gibba, EM. pi. 33. 17. f. 9 ? Ame- 

 rica and Europe. 



F. binodis (E.). — Parasitic, mostly 

 simple ; valves rostrate, sometimes con- 

 stricted, sometimes inflated at the middle; 

 striae wanting or obscure. EA. p. 127 ; 

 Microg. pi. 5. 2. f. 26. = Odontidium ? pa- 

 rasiticiim, SBD. ii. p. 19, pi. 60. f. 375. 

 Em'ope and America. /3 inflated, with- 

 out a central constriction. S /. c. p. 375. 

 Frustules rarely cohering, and scarcely 

 silicious. S. 



F. constricta (E.). — Frustules fre- 

 quently cohering by their angles ; valves 

 rostrate, subacute, in general slightly 

 constricted, sometimes inflated at the 

 middle ; striae faint, 42 in -001". EA. 

 p. 127; Microg. several figures. = F. 

 undata, SBD. ii. p. 24, pi 60. f. 377. 

 /3, valves turgid at the middle, S. Eu- 

 rope, Asia, Australia, and America. 



F. Fntomon (E.). — Valves elongated, 

 smooth, strongly constricted at the 

 middle, with rostrate ends. EA. p. 127 ; 

 Microg. pi. 6. 3. f. 52. North America. 



F. binalis, EM. pi. 14. f. 52. Germany 

 and Maiuitius. Valves smooth, con- 

 stricted at the middle, and roimded at 

 the ends. 



Doubtful and undescribed Species from 

 FJlirenberg. 



F. ? Tessella, EM. pi. 20. 2. f. 29. 

 Broadly and sharply lanceolate without 

 markings. 



F. ? Synedra, EM. pi. 39. 3. f. 60, 61. 

 Frustules united, curved ; venter gibbous 

 at centre. 



F. ? Mesogongyla, EB. 1856, p. 333, 

 f. 48. Africa. Valves ^\dth minute in- 

 flated middle, and slender acute rostrate 

 ends. 



F. oxyrluanbus, EB. 1856, p. 333, 

 f. 44, Africa ; F. Trachea, Australia ; F. 

 seininuda, fossil, Georgia ; F. ventralis, 

 Anatolia ; F. Himalayce, India ; F. ? 

 Stylus, ^gina ; F. ? Stylidium, ^gina ; 

 F. ? tmdulatum, Asia ; F. Crux, Asia ; 

 F. Tcenia, Africa ; F. amphilepta, Africa ; 

 F. Lamella, Australia; F. amphicephala, 

 Asia ; F. ventricosa, Africa ; F. frus- 

 tulia, America ; F. Funotia, Africa ; F. 

 thermalis, America; F. austral is, Ame- 

 rica; F. Pumerooni, America. 



Genus GRAMMONEMA (Ag.). — Frustules similar to those of Fragilaria, 

 but scarcely silicious, and united into flexible, highly mucous filaments. 

 " Grammonema in appearance comes very near to Fragilaria ; but its habit is 

 so very different that I am inclined, with Agardli, to keep them distinct. In 

 Fragilaria the filaments do not adliere well to paper, the frustules are silicious 

 and may be subjected to a red heat without an}- other alteration than tlic 



