276 Bacillariese, Naviculaceae, Frustulia. 



Italia (De-Toni) etc. — Pseudothallus globosus, gelatinosus, fru- 

 stula 1-5 seriata fovens. 



Species dubiae. 



2. Colletonema amphioxys (Ehr.) Kuetz. Bacill. p. 115, t. 28, f. 5, "BJ 



Species p. 105, Naunema amphioocys Ehrenb. Amer. t. 3, II, f. 5. 



— Ex fragmentis tantum cognitum; valvis acute-lanceolatis, fru- 

 stulis e facie connectivali visis parallelogrammis, oblongis, levibus. 



Hab. in aqua dulci regni mexicani (Ehrenberg). 



3. Colletonema americanum (Ehr.) Kuetz. Species p. 105, Naunema lifij 

 americanum Ehrenb. Bericht der Berl.Akad. 1845, p. 79. — Fru- 

 stulis maximis, 140 a. longis, linearibus, utrinque subacutis, in 

 tubulos ramosos dense consociatis, striatis; striis circ. 7 in 10 u.. 



Hab. in fluvio Hudsonio Americse borealis (Ehrenberg). 



4. Colletonema hibernicum 0' Meara in Quart. Microsc. Journ. XVI, ii58 

 p. 416 et in Just Bot. Jahresb. 1876, p. 67. — Tubulis simplici- 

 bus, frustulis inclusis minutissimis eximie naviculaceis; striis te- 

 nuissimis. 



Hab. in Hibernia (0' Meara). 



Species excludendae. 



5. Colletonema dubium Grun. in Wien. Verhandl. 1860, pag. 571, 

 t. 5, f. 16. 



Hab. in aqua stagnante vallis « Jauling» haud procul a a S. Veit 

 in Triesting» (Grunow). — Teste Grunow in Hedwigia VII, 1868, 

 p. 7, Naviculce Cesaiii adscribendum. 



6. Colletonema exile Grun. in Wien. Verhandl. 1860, p. 571, t. 5, 

 fig. 15. 



Hab. in aqua stagnante in aquario horti academici Vindobo- 

 nensis in Austria (Grunow). — Teste Grunow in Hedwigia VII, 

 1868, p. 7, Navicuke Cesatii adscribendum. 



7. Colletonema bullosum Fior. Mazz. in Atti Accad. pontif. N. Lincei 

 1857-62, I, t. 1, f. 1-5. 



Hab. in aquis acidulo-salso-bromuratis ad Terracinam Italiee. 



— Species, teste ipsa dom. E. Fiorini Mazzanti (Atti Soc. critt. ital. 

 1879, p. 104), in genus Amphoram transferenda. 



FRUSTULIA Ag. [1824] Syst. Alg. pag. XIII, l em. Grun. [1865] 

 Desm. Diat. ins. Banka p. 10 (Etym. a frustulo), De Toni Osserv, 



