237 
central depression in the middle of which is a roundish 
knob ; the turns distinctly visible on the lower disc, al- 
though neither they nor the cells are separated by sulci; 
on the uppersurface which is occupied, excepting the 
central part, by the last turn, the cells are a little convex 
with slight separating depressions. 0,04. Aberdeen. 
Grnus.—TEXTULARIA. Macweituivray. 
Subpyramidal, compressed, with the summit pointed. 
the base rounded, having on each side an angular 
or sinuous grove extending from the summit to the 
base, and composed of two series of alternating cel- 
lules ; the aperture semi-lunar on the inner side of 
each cellule. 
T. Ostonea. Macy. Aber. p. 38. Oblong lanceo- 
late, somewhat compressed, of two alternate vertical 
series of horizontal, rather convex, depressed, glossy, 
somewhat tuberculated olivaceous cells. 0,04...0,02. 
Aberdeen. 
T. Ostusa Macg. Aéer.p. 321. Rather broadly 
oblong, reddish white, subtruncated at the base, rounded 
at the apex, much compressed, sloping to the margins 
which are thin and subcarinated,; of about sixteen al- 
ternating cellules, disposed in two series, and horizontal, 
