110 BULLETIN 100, UNITED STATES NATIONAL MUSEUM 



NAVICULA MEXICANA (Heiden) Mann 



(Schmidt, Atlas, pi. 264, figs. 3, 7.) 



This is named in the above Caloneis mexicana, a genus the validity 

 of which is here denied. 



NAVICULA MIMULA, new name 



Plate 23, fig. 4 



As was mentioned under JV. mendica Mann, this diatom is probably 

 a variety of " Diploneis hiseriata CI." (Nav. Diat., vol. 1, p. 102, 

 pi. 2, fig. 16) although the biserial quality is here lacking, as there is 

 only a single series of beads on either side of the valve. But the 

 shape, general sculpture, including the hyaline apical areas and the 

 straight rhaphe in both, makes any specific distinction undesirable. 

 As has been said, Cleve's appropriation of the name hiseriata for this 

 form makes it necessary for those who do not follow his classification 

 to give another name to the present species, so as to avoid confusion 

 with Navicufa hiseriata Petit (Journ. Roy. Micro. Soc, 1878, pi. 14 

 fig. 15). It may be said at this place that the use of one specific 

 name for two diatoms that will undoubtedly be considered by some 

 diatomists as belonging to the same genus is as unfortunate as it is 

 unnecessary. 



Length, 0.093; width, 0.036; 3.6 lines in 0.01 mm. 



This diatom is rare. 



NAVICULA MIRABILIS Leuduger-Fortmorel 



(Leuduger-Fortmorel, Diat., Ceyl., p. 31, pi. 2, fig. 21.) 



This rare diatom, found heretofore only in Ceylon, should not be 

 confused with the later named (1879 and 1886) A T . mirahilis Castra- 

 cane (Chall. Exp., pi. 30, fig. 10). The last De Toni renames N. 

 philippinica (Syl. Alg., p. 87). 



NAVICULA MOLESTA, new species 



Plate 23, fig. 5 



Valve very convex, long-elliptical or fusiform in outline, with gently 

 curved sides and rounded apices ; markings of finely set, beaded lines, 

 all radial, almost reaching to the rhaphe, at the center more loosely 

 spaced, resulting in an imperfect, flaring, stauroslike, lateral exten- 

 sion of the central area ; rhaphe rigidly straight, its central ends 

 almost touching. 



Length, 0.085; width, 0.023; 18 lines in 0.01 mm. 



It has some resemblance to the much coarser, fresh-water, N. hott- 

 nica Grunow, the original material of which is in H. L. Smith, Types, 

 No. 682, and the original figure in Van Heurck's Synopsis, plate 7, 



