56 BULLETIN 100, UNITED STATES NATIONAL MUSEUM 



CHAETOCEROS AFFINE Lauder 



(Micro. Journ., 1864, pi. 8, fig. 5.) 



CHAETOCEROS BOREALE Bailey 



(Smith. Contrib., 1854, p. 8, figs. 22-23; Micro. Journ., 1860, pi. 2, fig. 18.) 



CHAETOCEROS CELLULOSUM Lauder 



See C. lorenziawus Grunow. 



CHAETOCEROS COARCTATUS Lauder 



(Micro. Journ., 1864, pi. 8, fig. 6; Cleve, Java Diat., pi. 2, fig. 10.) 



CHAETOCEROS CURVISETUM Cleve 



(Gran, Norsk. Exp., pi. 3, fig. 43.) 



CHAETOCEROS DIADEMA (Ehrenberg) Gran. 



(Gran. Protophyta, p. 20, pi. 2, figs. 16-18; Micro. Journ., 1856, pi. 7, figs. 

 49-52.) 



Only the endocysts of this pelagic diatom were found, what Ehren- 

 berg called Syringidium diadema (Mikrogeologie, 35A, pi. 18, fig. 13), 

 and in the second reference above. 



CHAETOCEROS FURCA Cleve 



(Cleve, Phytoplank., pi. 1, fig. 10.) 



CHAETOCEROS (BACTERIASTRUM) HEBES, new species 



Plate 11, fig. 7 



Valve circular, hyaline; central part slightly convex, below which 

 is set the ring of radiating arms ; the bases of these have strong insets 

 in the valve, producing a fictitious inner ring; they are stout, tapered, 

 straight, with blunt ends and are wound spirally with two thread-like 

 ridges set with spines and so spaced that the upper and under ridges 

 produce a criss-cross effect. 



Diameter of valve, 0.017 to 0.025 mm. ; with arms, 0.084 to 0.096 mm. 



Lauder's name, B. varians, has doubtless prevented observers from 

 detecting some actually distinct species of these circular forms of 

 Chaetoceros; for, although his species does vary, several types, like 

 the one here described, can not be looked upon as mere variations. 



Type.— Cat, No. 43605, U.S.N.M. 



CHAETOCEROS LORENZIANUM Grunow 



(Grunow, Neu. Ungen. Diat., p. 157, pi. 14, fig. 13; Van Heurck, Synopsis, 

 pi. 82, fig. 2; H. L. Smith, Types, No. 629.) 



Grunow's name, given in 1863, was followed the next year by 

 Lauder's C. cellulosus (Trans. Micro. Soc, 1864, p. 78, pi. 8, fig. 12). 

 A figure in Van Heurck's Synopsis, plate 82bis, figure 9, is incor- 

 rectly spelled C. lorenzii Grunow. 



