30 BULLETIN 100, UNITED STATES NATIONAL MUSEUM 



ASTEROMPHALUS AREOLATUS, new species 



Plate 6, fig. 5 



Valve slightly oval, the long axis coincident with the single dissim- 

 ilar radial arm. Seven arms in all, six of them broad, tapering to 

 the margin, with a very minute process at the marginal end, separated 

 by zig zag partitions where they join to form the central area, which 

 is one-third the diameter of the valve ; the dissimilar arm very nar- 

 row with a large process at its marginal end, its club-shaped inner end 

 passing beyond the center of the valve; beading very coarse, not 

 reticulated, the beads well separated, those bordering the arms larger 

 than the others, two to three beads wide at the inner end and six to 

 seven at the marginal end of each sector. 



Long diameter, 0.045 mm. 



This minute species has a general likeness to A. reticulatus Cleve 

 (Diat. Java, p. 5, pi. 1, fig. 2). It is, however, not reticulated, its arms 

 are dissimilar in shape and do not stop short of the margin but touch 

 it, where there are small but evident processes at the tips, apparently 

 lacking in Cleve's form. It is closer to the unnamed figure in 

 Schmidt's Atlas, plate 38, figure 9, one specimen found being identi- 

 cal with that figure. It is not rare in the Philippine Islands dredg- 

 ings, but its minuteness and delicacy make it difficult to find. Less 

 similar is A. rohustus Castracane (Accad. Pont. Nuovi Lincei, 1875, 

 pi. 6, fig. 5). 



Type.— Cat. No. 43582, U.S.N.M. 



ASTEROMPHALUS BEAUMONTII Ehrenberg 



(Schmidt, Atlas, pi. 38, figs. 6-7, misnamed. Fricke's index, p. 15.) 



The correct name is indicated by the opinion, cited in the above, 

 by Janisch. (See Mann, Diat. Alb. Voyages, p. 274.) 



ASTEROMPHALUS BROOKEI Bailey 



(Amer. Journ. Sci., 1856, p. 2, pi. 1, fig. 1; Schmidt, Atlas, pi. 38, figs. 21-23.) 



ASTEROMPHALUS ELEGANS Greville 



(Quart. Journ. Micro. Sci., 1859, pi. 7, fig. 6; Schmidt, Atlas, pi. 38, figs. 1-2.) 



ASTEROMPHALUS HILTONIANUS (Greville) Ralfs 



(Rattray, Rev. Cose, p. 213; H. L. Smith, Types, No. 49.) 



ASTEROMPHALUS RETICULATUS Cleve 



(Cleve, Java Diat., p. 5, pi. 1, fig. 2.) 



ASTEROMPHALUS ROPERIANUS (Greville) Ralfs 



(Schmidt, Atlas, pi. 38, fig. 15; Micro. Journ., 1860, pi. 4, fig. 14.) 



