80 



The Naturalist. 



E. ansatum, Ehr. 



E. didelta, E. 



E. oblongum, E, 



Arthrodesmus convergens, Ehr, 



A. incus, Hs. 



Docidium baculum, Breb. 



D. clavatum, Kz. 



D. clavatum, var. B. with, projecting 



suture 

 D. nodulosum, Breb. 



* Cosmarium truncatellum, Perty 

 C. undulatnm, var. minutum, Wittr. 

 C. botrytis, Men. 



C. margaritiferum, Men. 



C. orbiculatum, R. 



C. globosum, vel. bioculatum, Breb. 



C. cucumis, Cor. 



C. Meneghinii, Breb. 



C. quadratum. Breb. 



C. cucurbita, Breb. 



C. pyramidatum, Breb. 



C. undulatum, var., Cor. 



C. crenatum, R. 



C. ornatum, var., R. 



* C. proemorsura, Breb. 

 C. amoenum, Breb. 

 Xanthidium armatum, Breb. 

 X. cristatum, Breb. 



X. fasciculatum, Ehr. 

 X. fasciculatum, var. B. polygonum, 

 Ehr. 



X. oetocome, Ehr. 



Staurastrum teliferum, R. 



S. orbicular e, R. 



S. punctulatum, Breb. 



S. alternans, Breb. 



S. dejectum, Breb. 



S. arachne, R. 



S. Iseve, E. 



S. avicula, Breb. 



* S. inflexum, Breb. 



* S. anatinum ? C. and W. 

 S. margaritaceura. Men. 



S. furcigerum, Breb. 



* S. pseudo-furcigerum ? Eeinsch 

 S. polymorphum, Breb. 



S. cristatum, Breb. 

 S. hirsutiim, Breb. 

 S, aculeatum. Men. 



* S. megacanthum ? Ld. 

 S. tetracerum, E. 



S. gracile, E. 



* fe. Sebaldi, Eeinsch 



* S. Pringsheimii ? Eeinsch 

 S. pilosum, A. 



S. aversum (or brevispina, Breb.) Ld. 



S. spinosum, Breb. 



S. paradoxum, Meyen 



Penium Brebissonii, Men. 



P. digitus, Breb. 



Closterium setaceum, Ehr. 



C. lineatum, Ehr. 



C. lunula, Ehr. 



C. Dianas, Ehr. 



C. acutum, Breb. 



C. costatum, Cor. 



C. juncidum, E. 



C. angustatum, Kz. - 



C. Leibleinii, Elz. 



C. attenuatum, Ehr. 



Tetmemorus Brebissonii, R. 



T. granulatus, E. 



Spirotsenia condensata, Breb. 



PosrcEiPT. — Since compiling my lists in September I have to make the 

 following additions, &c. : Xanthidium aculeatum (Ehr.) ; X. Brebissonii 

 (R.) var. /3 ; Staurastrum cuspidatum ; S. polymorphum (both Breb.) ; 

 S. vestitum (R.) .The existence of S. Pringsheimii I have proved by 

 finding other specimens. I find that the specimen on plate, fig. 19, is 

 Staurastrum dejectum, var. y connatum (Lundell, Desm. Suec), a variety 

 new, I believe, to England. One curious form occurs, a Micrasterias, 

 apparently combining the characters of M. crenata and M. truncata. 

 Concerning these, Ralfs says, p. 76, " I have seen some specimens which 

 make it doubtful whether they be really distinct." The gathering is yet 

 far from being exhausted," for I have a number of forms which still 

 defy my efforts to clear up their identity. To the Diatoms are added 

 Nitzschia lanceolata, N. minutissima^ Navicula amphirhynchus, and 

 Stauroneis phsenicenteron. 



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