16 BULLETIN 100, UNITED STATES NATIONAL MUSEUM 



Schmidt's Atlas is correctly included here, it being nothing more 

 than an immature valve. 



ALLONITZSCHIA, new genus 



Valve elongated, bilaterally unsymmetrical, tapering to the slightly 

 curved apices, NitzscMa-\ike ; its dorsal side straight, ornamented 

 with a closely set row or chain of polygonal divisions forming a heavy 

 border, slightly over one-half the width of the valve and proportion- 

 ally decreasing in size toward the gracefully tapered apices; ventral 

 side slightly convex, its margin gently undulate, the undulations 

 corresponding to barely perceptible elevations and depressions or 

 waves of the valve surface running across the valve and correspond- 

 ing in number to the polygonal divisions of the dorsal border; the 

 whole valve, including this border, covered with fine transverse rows 

 of beading. 



Side (girdle) view narrow rectangular, the lines or costae of the 

 polygonal dorsal border of the valve here appearing as septal thick- 

 enings, thereby having the appearance of crossbars, like those seen in 

 girdle views of Denticula lauta, Epithemia zebra, etc. 



ALLONITZSCHIA MUNIFICA, new species 



Plate 2, fig. 3 



Characters those of the genus. I found but one species and after 

 much searching could obtain only a single specimen ; but fortunately 

 this was a complete frustule. Its general appearance is near to that 

 of Nitzschia, or to that section of it now generally classed as Hantz- 

 schia, as the striking row of polygonal divisions forming a border 

 along one edge is on the same side, not the opposite side, of each 

 valve of the frustule. 



Length of valve 0.118; widths 0.010; dorsal division 1.4 in 0.01; 

 beaded lines 9 in 0.01 mm. 



Found at Jolo Jolo, Sulu Islands. 



Type.— Cat. No. 43566, U.S.N.M. 



Genus AMPHIPRORA Ehrenberg 



Exclusive of those forms which seem to me rightly to be included 

 by Cleve in his new genus, Tropidoneis, which see. 



AMPHIPRORA LIMPIDA, new species 



Plate 3, fig. 1 



Valve of characteristic shape, nearly bisected by the middle sinus, 

 the two arched halves having a broad heavy rim along the dorsal side 

 beaded on its lower edge; the inner ventral edge of the valve nearly 

 straight but curving slightly at the ends, and bordered by a heavy 



