Bacillarieae, Naviculacese, Pleurosigma. 261 



ttab. in aquis marinis et submarinis ad oras Angliae et Hiber- 



nias (W. Smith, Thwaitbs), Galliae (Brebisson), ad «Anvers» Bel- 



gii (Vanburck), Hispaniae (Truan), ad oras Americae (Sullivant), 



in ostio fluvii Demerara in Gujana (Ehrenberg, Kuetzing). 



98. Pleurosigma scalproides Rabenh. Alg. n. 1101, Fl. Eur. Algar. 1098 

 I, p. 241, V. H. Syn. p. 119, t. 21, f. 1, Perag. Pleuros. t. 8, f. 31, 

 Truan Diat. Astur. p. 52, t. 3, f. 14. — Mediocre v. parvum; val- 



vis e sigmatoideo-lineari lanceolatis, 45-62 » 10, ad utrumque finem 

 parum attenuatis, apicibus obtuso-rotuudatis, rhaphe vix excentrica, 

 nodulo centrali oblongo; striis transversis validis circ. 22, longitudi- 

 nalibus circiter 29 in 10 u. (teste Van Heurck). 



Hab. ad ripas fluminis Albis prope Dresdam (Hantzsch), prope 

 Francofurtum ad Moenum (Fresenius), circa « Briinn » Moravia) 

 (Nave), in Italia (De-Toni), Galicia (Gutwinski) et Polonia (Lopott). 

 — Pleurosigmati eximio proxime affine nisi idem. Huc pertinere 

 videtur Colletonema subfiexile Greg. in Habirsh. Chase Catal. 

 Diat. (Exemplar Debyanum) p. 72, Schizonema subflexile (Greg.) 

 Rabenh. Fl. Eur. Algar. I, p. 266, quaa species a Pleurosigmate 

 eximio (Thw.) Grun. vix. differt rhaphe subflexuoso-sigmatoidea 

 striisque 19-20 in 10 u. Ad « Gleushira» prope ulnverary» Sco- 

 tise (Gregory). 



Species mihi minus notae. 



99. Pleurosigma curvulum (Ehr.) Ralfs in Pritch. Inf. p. 917, Rabenh. 1099 

 Fl. Eur. Algar. I, p. 241 nec Grun., Navicula curvula Ehr. Inf. 



p. 181, n. 230, t. XIII, f. XIV non Kuetz., Gyrosigma curvulum 

 Rabenh. Siissw. Diat. p. 47, t. V, f. 8. — Valvis anguste lineari- 

 sublanceolatis, ad 60 u. longis, sigmatoideis, apicibus obtuso-trun- 

 catis, rhaphe subexcentrica, nodulo centrali minuto rotundato ; 

 striis transversis subtilissimis, 21-23 in 10 u., longitudinalibus 

 obsoletis. 



Hab. in fossis, aquis quietis per Germaniam, Poloniam, Italiam 



etc. passim. 



100. Pleurosigma Smithianum Castrac. Diat. Challenger p. 38, t. 28, noo 



f. 6, Notarisia 1889 p. 691. — Valvis lanceolatis, 105-20 (ex 

 icone), acutis, aduncis; rhaphe sigmoidea, ad centrum oblique trans- 

 versa, dein submarginali. 



Hab. ad portum «Tahiti» (Exped. Challenger). 



101. Pleurosigma lamprocampum (Ehr.) Ralfs in Pritch. Inf. p. 917, noi 

 Rabenh. Fl. Eur. Algar. I, p. 237, Perag. Pleuros. t. 8, f. 13 b, 



