20 BULLETIN 100, UNITED STATES NATIONAL MUSEUM 



bowed, its central and terminal nodules adjacent to the ventral edge; 

 no hyaline area; markings transverse, very closely set, slightly wavy; 

 costae obscurely cross-striated. 



Length, 0.144; width, 0.028; lines, 7.2 in 0.01 mm. 



A plump, robust form, simulating some of the insect larvae. 



Type— Cat. No. 43571, U.S.N. M. 



AMPHORA CORPULENTA Cleve and Grove 



(Le Diat., vol. 1, p. 68, pi. 10, fig. 14.) 



This species is common in the Philippine Islands. The original was 

 found at the not far distant Macassar Straits. 



AMPHORA COSTATA W. Smith 



(Smith, Brit. Diat,, pi. 30, fig. 253.) 



I do not agree with Cleve's idea of this being like A. cymbifera 

 Gregory the same as A. erebi Ehrenberg (Mikrogeologie, 35A, pi. 

 23,fig.2). This last is practically indeterminate and came from the 

 Arctic, namely, Assistance Bay. Gregory's form is figured in Di- 

 atoms of the Clyde, plate 14, figure 97. 



AMPHORA CRASSA Gregory 



(Geogory, Diat., Clyde, p. 524, pi. 14, fig. 94; Schmidt, Atlas, pi. 28, fig. 16.) 



Man}^ varieties of this inconstant species were found, including the 

 form peculiar to Campeche Bay and called by Grunow, var. cam- 

 pechiana. 



AMPHORA CUCUMERIS, new species 



Plate 3, fig. 7 



Valve stout, almost cylindrical, with blunt ends which are only 

 e lightly bent toward the ventral (rhaphe) side ; convex on the dorsal 

 side, the ventral barely convex or straight except for a shallow sinus 

 at the middle; markings coarse longitudinal rows of heavy beads, six 

 to seven rows, the space between the two median ones wider than 

 between the others, thus producing a longitudinal, median hyaline 

 line; rhaphe in general parallel with the ventral margin. No com- 

 plete frustule was found; hence the character of the connecting zone 

 is not known. 



Length, 0.092; width, 0.026; rows of beading, 3.G in 0.01 mm.; 

 beads in each row, 3 in 0.01 mm. 



This very stout diatom with its valves curiously like the rough 

 cucumber known as the gherkin, belongs to the group of Amplioras 

 of which A. crassa Gregory is the type. It can not, however, be as- 

 signed to any hitherto described species. It is rare in the Philippines. 



Type— Cat. No. 43572 U.S.N.M. 



