MARINE DIATOMS OF THE PHILIPPINE ISLANDS 27 



AMPHORA RECESSA, new species 



Plate 5, fig. 2 



Dorsal side of valve slightly and evenly convex, ventral slightly 

 biconcave; ends narrow, rounded; rhaphe double-bowed, generally 

 parallel to the ventral edge, its outer ends thickened but without 

 beads and not reflected; markings of fine closely set moniliform 

 costae along the dorsal side, but leaving a hyaline space of equal 

 width along the ventral side, except at the middle, where a wedge- 

 shaped extension reaches nearly to the central nodule; girdle (back) 

 marked with two to three very delicate longitudinal, widely separated 

 lines of beading. 



Length, 0.155; width, 0.020; width of frustrule, 0.056; lines, 9 in 

 0.01 mm. 



This delicate species belongs in the A. proteus group. It has some 

 resemblance to one shown in Schmidt's Atlas, plate 27, figure 37, and 

 plate 27, figure 65, two varieties of A. pellucida Gregory. 



Type.— Cat. No. 43579, U.S.N.M. 



AMPHORA RECTANGULARIS Greville 



(Greville, So. Pac. Diat., pi. 2, fig. 10.) 



AMPHORA RHOMBICA Kitton 



(Schmidt, Atlas, pi. 40, fig. 39.) 



AMPHORA SCHMIDTII Grunow 



(Schmidt, Atlas, pi. 28, fig. 3.) 



The original of this species was from Campeche Bay. 



AMPHORA SIMA, new species 



Plate 5, fig. 5 



Valve plump, massive, smoothly convex on dorsal side and bicon- 

 vex on the ventral side; ends blunt, reflexed, flattened; rhaphe 

 closely adjacent to the ventral edge; markings of heavy transverse 

 costae without cross-striation, but having a single bead in the mid- 

 dle^of each costa, the beads thereby forming a median line bisecting 

 the valve longitudinally. 



Length, 0.195; width, 0.043; lines, 3.5-4 in 0.01 mm. 



Type.— Cat. No. 43580, U.S.N.M. 



A. labuensis Cleve (Vega Diat., p. 493, pi. 35, fig. 1&) is a close rela- 

 tive of this, but its costae are striated, and lack the median row of 

 beads, the ends also are not flattened and reflexed like the present 

 species. There is some relation between it and A. areolata Grunow 

 (LeJDiat., pi. 22, figs. 1-4). 



