260 Bacillarieae, Naviculaceae, Pleurosigma. 



achroum ; valvis 198=22, acutiusculis, rectis ; striis sub angulo recto 

 intersectis, striis transversis 19, longituditialibus 21 in 10 u.. 



Ilab. in mari Kariano ad Caput « Wankarema » (Cleve); in 

 mari Adriatico (Grunow) ; ad insulas « Seyschellen » et Australiam 

 (Grunow). — An Navicula? 



** Species aquae dulcis incola. 



96. Pleurosigma Parkerii Harrison in Micr. Journ. 1860, p. 104 c. 1096 

 icone, Rabenh. Fl. Eur. Algar. I, p. 240, Cl. et Gr. Arct. Diat. 



p. 57, V. H. Syn. p. 118, t. 21, f. 10, Truan Diat. Astur. p. 51 

 t. 3, f. 13, Perag. Pleuros. t. 8, f. 33. — Parvum; valvis sublate 

 lanceolatis, 80-130 s 18-21, sigmatoideis, stramineis, apicibus longe 

 • acuminatis productis subacutis, rhaphe excentrica, nodulo cen- 

 trali rotuudato, oblongo; striis transversis validis 19-22 in 10 y.., 

 longitudinalibus tenuibus, 22 et ultra in 10 u. 



Hab. in aquis dulcibus Angliae « Thornton-le-Moor, Lincolnshire » 

 (Parker), ad « Anvers et Hasselt» Belgii (Van Den Born, Van 

 Heurck), in Hispania(TRUAN), pr. « Stockholm » Sueciae (Nordstedt); 

 forma minor e Rengalia Asise (Grunow). — Var. stauroneoides 

 Grun. in Cl. et Gr. Arct. Diat. p. 57: paullo minus, striis longi- 

 tudinalibus 21, transversis 24 in 10 u.., nodulo centrali utrinque 

 stauriformi-producto sed stauro striato. In fl. «Hudson River» 

 dicto Americae. Species insignis ab omnibus aquae dulcis distin- 

 ctissima. 



Subsectio B. [Endosigma] Frustula intra tubulos gelatinosos inclusa; 

 valvae breves, ventricosae. 



97. Pleurosigma eximium (Thwait.) Gruu. et Cl. Arct. Diat. p. 61, 1097 

 V. H. Syn. p. 119, t. 21, f. 2, Pleurosigma oblnsalum Sulliv. 



in Amer. Journ. XXVII, p. 251, Truan Diat. Astur. p. 51, t. 3, 

 f. 11, Pritch. Inf. p. 919, Endosigma eximium Breb. mscr., Schi- 

 zonema eximium Thwait. in Ann. Nat. Hist. 1848, p. XII, Rabenh. 

 Fl. Eur. Algar. I, p. 266, Colletonema eximium (Thwait.) Kuetz. 

 Species p. 891, W. Sm. Br. Diat. II, p. 69, t. 56, f. 350, Pritch. 

 Inf. p. 926, t. 8, f. 43, Glceonema sigmoides Ehr. Abh. 1845, 

 p. 78, Encyonema sigmoides Kuetz. Species p. 62. — Valvis 

 brevibus, linearibus, 50-60^10-12,5, apicibus sigmoideis, obtusis- 

 simis, nodulo centrali minimo, rhaphe valde sigmoidea triplici ; striis 

 transversis 23-25 in 10 u., mediis subradiantibus, omnibus rhaphen 

 attingentibus, parallelis, rectis, striis longitudinalibus 27-28 in 10 u. 



