208 Bacillarieae, Naviculaceae, Stauroueis. 



Hab. ia Islandia (Ehrenberg). — Mihi plane ignota. 



19. Stauroneis Gregoryi Ralfs in Pritch. Inf. p. 913, Cl. et Gr. Arct. 

 Diat. p. 47, t. 3, f. 64, V. H. Syn. p. 68, t. A, f. 4, Stauroneis 

 amphioxys Greg. in Trans. Micr. Journ. 1356, p. 48, t. V, f. 23, 

 Lagerst. Bohusl. Diat. p. 47, f. 5, Grun. Diat. Kasp. p. 17 [non Stau- 

 roptera amphioxys Ehr., qua? Naviculam sistit]. — Valvis rhom- 

 boideo-lanceolatis, 50-100 a. longis,, utrinque v. acuminatis v. ob- 

 tusulis, area lineari ad valvarurn marginem extensa; striis trans- 

 versis subradiantibus, parallelis, 16-20 in 10 u.., rhaphen simplicem 

 attingentibus, subtiliter granulatis. 



Hab. in Scotia (Gregory), in sinu «Baku» maris caspici (Gru- 

 now), in aquis subsalsis ad uBlankenberghe» Belgii dubie (Van 

 Heurck). — Ad Pleurostauron vergit. Cfr. var. ? dimidiata Grun. 

 in Cl. et Moll. Diat. n. 247 et var. ? diminuta Grun. 1. c. n. 255. 



20. Stauroneis robusta Petit Cat. p. 27, t. 5, f. 16, Hedwigia 1878, 

 p. 130. — Valvis ellipticis, 90-100 s 28, abrupte apices versus acu- 

 minatis, rhaphe recta, nodulo centrali pro ratione magno, nodulis 

 terminalibus parvis et paullo sub polis sitis ; stauro e centro 

 margines versus dilatato, margines non attingente; striis transversis 

 per areas albas, leves, longitudinales interruptis, fere 7 in 10 u.., 

 margine annuliformi omuino striato; frustulis e facie connectivali 

 visis medio valde constrictis, apices versus late rotundatis. 



Hab. in freto «Foveaux» Novae Zelandiae. 



21. Stauroneis decora Grev. Diat. South Pacif. III, p. 236, t. 3, f. 11. 

 — Valvis oblongo-ellipticis, ad 130 u.. longis, in apices subacutos 

 leniter productis, in utroque latere rhaphes linea gracillima orna- 

 tis, nodulo centrali in staurum parvum brevem angustissimum di- 

 latato; striis transversis quam maxime subtilibus, parallelis, sub- 

 inconspicuis. 



Hab. in mari Novae Caledoniae (Roberts). — Frustula hyalina. 



22. Stauroneis obtusa Lagerst. Diat. Spetsb. p. 36, t. 1, f. 11, Hedwi- 

 gia 1874, p. 120. — Frustulis e facie connectivali visis rectangu- 

 laribus, lateribus leniter concavis, angulis rotundatis; valvis lan- 

 ceolatis, apicibus obtusis vel truncato-obtusis, 62-68-10-11, no- 



dulo ceutrali ?; nodulis terminalibus parvis rotundatis; rhaphe 



e lineis duabus subrectis composita; striis transversis subrectis, 

 nodulum centralem versus convergentibus, 18-19 in 10 u., in me- 

 dia valvarum parte deficientibus; area transversali margines ver- 

 sus dilatata, hos attingente, longitudinali lineari, regione infra api- 

 ces parva exstria. 



