140 BULLETIN 100, UNITED STATES NATIONAL MUSEUM 



Genus PODOCYSTIS Kutzing 



PODOCYSTIS SPATHULATA (Shadbolt) Van Heurck 



(Van Heurck, Treat., p. 365; Peragallo, Diat., France, p. 261, pi. 68, fig. 12.) 



The two above citations taken together go far toward clearing up 

 a confusion of long standing regarding the two species of Podocystis — 

 the one here recorded and P. adriatica Kutzing. De Toni and 

 others (Syl. Alg., p. 601) consider these and Bailey's P. americana 

 to be P. adriatica; but as Van Heurck points out, that species is 

 sharply distinct from Shadbolt 's Euphyllodium spathulatum as fig- 

 ured in the Microscopical Journal for 1854, plate 1, figure 3, and 

 excellently reproduced in the above citation in Peragallo 's Dia- 

 tomees de la France, where it is shown in contrast with the typical 

 P. adriatica (fig. 11). This last has double or threefold rows of fine 

 beading, the rows separated by costal lines; while the present species 

 has single rows of coarse rectangular beading without separating 

 costal lines. There is also in this species (not always, as Van Heurck 

 implies, but very often) a heavy network of anastomosing costal bars 

 which does not in reality belong to the surface of the valve but lies 

 beneath the beading as a sort of craticular plate. P. spathulata is 

 generally balloon shaped ; and as the American species of P. adriatica 

 are also balloon shaped, instead of cuneate like Ktitzing's type, Bailey 

 considered he had a new species and called it P. americana. (New Sp. 

 and Loc. Diat., pi. 1, fig. 38.) But his exceptionally good figure shows 

 it to have the two to three rows of fine beading separated by costal 

 lines of P. adriatica. H. L. Smith's Type, No. 418, the American 

 form, also is conclusive as to this marking. A third name — 

 P. australica Witt (figured in his Diatomaceen Siidsee, Journ. Mus. 

 Godeff., 1873, p. 70, pi. 8, fig. 10) — is evidently the same as Bailey's 

 form. We have therefore at present two species, P. spathulata (Shad- 

 bolt) Van Heurck, and P. adriatica Kutzing, including Bailey's Ameri- 

 can variety of this, resembling only in contour the other species. 



Genus PORPEIA Bailey 



PORPEIA QUADRICEPS Bailey 



(Pritchard, Inf., pi. 6, fig. 6; Greville, New and Rare Diat., pi. 6, figs. 18- 

 19; Schmidt, Atlas, pi. 142, figs. 46-56.) 



Genus PSEUDO-EUNOTIA Grunow 



PSEUDO-EUNOTIA DOLIOLUS (Wallich) Grunow 



Plate 30, figs. 7-8 



(Van Heurck, Synopsis, pi. 35, fig. 22; Peragallo, Diat., France, pi. 82, fig. 27.) 

 This is much nearer to the genus Synedra than to Eunotia. 



