48 BULLETIN 100, UNITED STATES NATIONAL MUSEUM 



near the margin, then sloping diagonally downward; in side (girdle) 

 view the three flat-topped horns are seen to be notched near the 

 top on the outside ; sides of the valve hyaline like its upper surface ; 

 girdle densely covered with rows of beading running vertically, that is, 

 across it. 



Diameter of valve (measured from apex to opposite side), 0.045- 

 0.082 mm. ; height of frustule, 0.056-0.073 mm. 



This species, which is of the Triceratium castelliferum group resem- 

 bles most nearly one of the figures of T. turriferum Truan and Witt, 

 as given in their Diatomaceen von Hayti, plate 7, figure 6. 



Type.— Cat. No. 43600, U.S.N. M. 



BIDDULPHIA UNDULOSA, new species 



Plate 11, fig. 3 



Valve broadly oval, convex, its margin strongly undulating, or 

 more correctly, scalloped, the indentations being broadly curved, but 

 the external points of union between the scallops being acute angles; 

 a short pedicelled horn set close to the margin at either end of the 

 valve ; surface of valve dusted over with an exceedingly fine rugosity 

 and evenly covered with thickly set sharp but very short prickles; the 

 girdle, joining the two strongly convex valves, is ribbed to correspond 

 with the undulations of the rim of the valves, and is more coarsely 

 rugose than it, but destitute of prickles. 



Length, 0.089; width, 0.076 mm. 



Comparison may be made with B. punctata Greville from Oamaru, 

 New Zealand (Schmidt, Atlas, pi. 141, figs. 2-3). 



Type.— Cat. No. 43601, U.S.N. M. 



Genus CAMPYLODISCUS Ehrenberg 



CAMPYLODISCUS ADORNATUS A. Schmidt 



(Schmidt, Atlas, pi. 51, fig. 5; pi. 52, fig. 3; Deby, Campy., pi. 3, fig. 21.) 

 This is rather too close to C. ornatus Greville to justify a separate 



name. It is another of the forms found in both Campeche Bay and 



the Philippine Islands. 



CAMPYLODISCUS ADRIATICUS Grunow 



(Schmidt, Atlas, pi. 16, figs. 13-16, 18; Deby, Campy., pi. 5, fig. 34.) 



CAMPYLODISCUS AMBIGUUS Greville 



(Micro. Journ. vol. 8, p. 31, pi. 1, fig. 5; Schmidt, Atlas, pi. 18, figs. 21-26; 

 pi. 51, fig. 14.) 



It is an open question if it is best to follow De Toni's plan of unit- 

 ing this with 0. latus Shadbolt. Compare the original figures and 

 descriptions of the two in the Microscopic Journal for 1854, page 16, 

 plate 1, figure 13, and that Journal for 1860, page 31, plate 1, figure 5. 



