Bacillarieae, Cymbellaceae, Encyonema. 371 



ENCYONEMA Kuetz. [1833] Syn. Diat. p. 61 (Etym. encyos gravidus 

 et nema filamentum), Rabenh. Fl. Eur. Algar. I, p. 85, V. H. Syn. 

 1885, p. 65, De-Toni Osserv. tasson. Bacill. p. 899, Gloeonema 

 Ehr. [1838] Infus. et [1840] Ber. Berl. Akad. 1840 p. 211, nec 

 Grev. [1822], Monematis sp. Berk., Schizonematis, Frustulioe, 

 Cocconeidis, Cocconematis, Cymbelkv sp. auct. veter. nonuull., 

 Cymbella Ag. sectio Encyonema Brun Diat. Alp. 1880, p. 55. — 

 Frustula plerumque intra tubos mucosos simplices vel parce di- 

 visos congregata et subseriata, valvse plus minus cymbiformes, 

 per rhaphen in partes 2 inasquales divisse, nodulo centrali excen- 

 trico. nodulis terminalibus ab apicibus remotis; phaeophora ut in 

 Amphora. 



Obs. Sub uomina Cymbellce Encyonematis cl. Heiberg (Consp. 

 Diat. p. 110) oinnes fere species Encyonematis collegit. 



1. Encyonema prostratum (Berk.) Ralfs in Ann. and Mag. I, 16, p. 182, 1489 

 t. XVIII, f. 3, Rabenh. Sussw. Diat. pag. 24, t. VII, fig. 1, Alg. 

 n. 321 et 1247, W. Sra. Br. Diat. II, p. 68, t. 54, f. 345, Hass. 

 Alg. p. 439, t. 100, f. 10, A. Schm. Atlas t. 10, f. 64-66, t. 71, 

 f. 6-9, Pritch. Inf. p. 878, t. 7, f, 49, t. 14, f. 22, Kirch. Alg. 

 Schles. p. 189, V. H. Syn. p. 65, t. 3, f. 9-11, Truan Diat. 

 Astur. t. 1, f. 12. Monema prostratum Berk. Brit. Alg. t. IV, f. 3 

 (1832), Schizonema prostratum Grev. in Hook. Brit. fior. II, 

 p. 414, Encyonema maximum Wartm. Cryptogam. n. 29, A. Schm. 

 Atlas t. 10, f. 67-69, Glceonema prostratum Ehr., Encyonema 

 paradoxum Kuetz. Syn. Diat. t. 7, f. 33, Bacill. p. 82, t. 22, 

 f. 1, Sp. p. 61. — Valvis magnis, 50-90 u. longis, margine 

 dorsuali valde inflato, ventrali leniter arcuato, apicibus abrupte 

 attenuatis, obtusK rectis vel latus ventrale versus arcuatis, rha- 

 phe recta, apicibus centralibus latus dorsuale versus subincurvis, 

 area hyalina ampla circa nodulum centralem valde dilatata cincta; 

 nodulis terminalibns conspicuis, longe versus latus dorsuale pro- 

 longatis, omnino striis cinctis, excepto loco ubi rhaphen attingunt; 

 striis 6-8 in 10 </.., validis, costas simulantibus, transverse divisis, 

 saepe prope nodulum centralem passim abbreviatis; frustulis ple- 

 rumque tubo simplici inclusis. 



Hab. in aquis dulcibus per totam Europam passim, imprimis 

 in Helvetia (Naegeli, Brun), Britannia (Berkeley, Ralps, Has- 

 sall, W. Smith, Greville), Belgio (Van Heurck), Germania 

 (Kuetzing, Wartmann, Kirchner), Italia (Meneghini, De-Toni), 



