MARINE DIATOMS OF THE PHILIPPINE ISLANDS 129 



NITZSCHIA ZEBUANA, new species 



Plate 28, fig. 7 



Valve linear, with rounded ends; median indentation barely evident ; 

 very delicate transverse lines along both dorsal and ventral sides; the 

 the median portion, about one-third the width of valve, hyaline 

 or very faintly lined; dorsal band very narrow and marked with fine, 

 distant crosslines. 



Length, 0.139; width, 0.015; fine lines, 27 in 0.0J ; coarse dorsal 

 lines 10-11 in 1.01 mm. 



It is possible this may be related to N. plana, var. zebuana Castra- 

 cane (Chall. Exp., p. 67, pi. 13, fig. 10) the measurements and fineness 

 of markings of which are not given. At any rate, that form is too 

 wide from N. plana W. Smith to be accepted as a varity. (See 

 Smith, Brit. Diat., vol. 1, p. 42, pi. 15, fig. 114.) 



Type.— Cat. No. 43667, U.S.N.M. 



Genus OMPHALOPSIS Greville 



OMPHALOPSIS AUSTRALIS Greville 



(Greville, Diat., So. Pac, p. 537, pi. 1, figs. 10-11; Van Heurck, Treat., p. 335, 

 fig. 92.) 



This rare diatom has been previously found only in the Seychelles 

 Island and Woodlark Island, new Guiana. The genus is closely allied 

 to Plagiogramma. 



Genus PLAGIOGRAMMA Greville 



PLAGIOGRAMMA ANTILLARUM Cleve 



Plate 29, fig. 1 



(Cleve, Diat. W. I., pi. 3, fig. 16; not Schmidt, Atlas, pi. 209, fig. 10.) 



Schmidt's figure above should not be referred to this species. A 

 somewhat finer beaded variety of P. antillarum is named P. truanii 

 Pantocsek (Hung. Diat., vol. 3, pi. 15, fig. 224.) 



PLAGIOGRAMMA APPROXIMATUM A. Schmidt 



See under P. polygibbum Cleve and Grove. 



PLAGIOGRAMMA ATTENUATUM Cleve 



Plate 29, fig. 2 



(Cleve, W. I. Diat., p. 10, pi. 3, fig. 18.) 



This rare diatom was found in the nearby island of Ceylon and 

 the type in St. Bartholomew, W. I. It is here illustrated, as the 

 original figure by Cleve is poor. 



