MARINE DIATOMS OF THE PHILIPPINE ISLANDS 145 



Genus SKELETONEMA Greville 



SKELETONEMA MEDITERRANEANUM (Grunow) Brun 



(Van Heurck, Synopsis, pi. 91, figs. 3, 5; Schmidt, Atlas, pi. 180, figs. 38-39.) 



The question of placing this diatom here or under Melosira is 

 about evenly balanced. Grunow and Schmidt favor Melosira, Brun 

 and De Toni Skeletonema. If we take Greville's own idea of Skele- 

 tonema as based on S. barbadense (Micro. Journ., 1865, p. 43, pi. 5, 

 fig. 1) this species can not be held generically separate. But if we 

 compare it with more extreme forms, as S. costatum (which, strange 

 to say, Greville puts in Melosira) or with S. mirabile, this assign- 

 ment becomes questionable. A good illustration of the tangle of 

 Melosira and Skeletonema for forms of this kind is to be found in 

 Van Heurck's Synopsis, plate 91, figures 3, 4, 5, 6, and in Schmidt's 

 Atlas, plate 180, figure 33, and plate 180, figure 40. 



SKELETONEMA MIRABILE Grunow 



(Van Heurck, Synopsis, pi. 83, ter, fig. 5.) 



This essentially arctic diatom must have made its way to the 

 Philippine Islands by the Japan current, it having been found pre- 

 viously only at Cape Wankarema. 



Genus STEPHANOPYXIS Ehrenberg 



STEPHANOPYXIS ACULEATA (Ehrenberg?) Grunow 



(Schmidt, Atlas, pi. 130, fig. 12.) 



This should be distinguished from " Steplianopyxis aculeata" Ehren- 

 berg in Mikrogeologie, plate 18, figure 124, which is an indeterminate 

 figure, possibly a Xanthiopyxis. (Consult Grunow, Diat. F. Jos. 

 Land, p. 91.) 



STEPHANOPYXIS BRUNII A. Schmidt 



(Schmidt, Atlas, pi. 164, fig. 5; Van Heurck, Belgica, pi. 6, figs. 90, 92.) 



Though originally found in the fossil deposit at Sendai, Japan, 

 Van Heurck subsequently found it in Antarctic dredgings. This 

 third locality discovered is as incongruous as the two others. 



STEPHANOPYXIS TURRIS (Greville) Ralfa 



(Pritchard, Inf., p. 826, pi. 5, fig. 74; Schmidt, Atlas, pi. 130, figs. 42-43; 

 Grunow, Diat. F. Jos. Land, pi. 5, fig. 7.) 



This diatom is widely distributed and supplies many variations, 

 some of which are identical with figures of S. appendiculata Ehren- 

 berg. as for example, those in Schmidt's Atlas, plate 130. But 

 Ehrenberg's figure in his Mikrogeologie, plate 18, figure 4, is not at 

 all similiar. De Toni unites the two but gives preference to the 

 later name, which was created by Greville in a note added to 

 Gregory's Diatoms of the Clyde, page 538. 



