Biconvex test with low trochospiral coil of 3 to 4 volutions, spiral side evolute, umbilical side involute.
Genera of order “Rotaliida”
Test biconvex, lenticular with prominent radial spines.
Test globular but the three or four large thick and protruding spines may give a triangular to tetrahedal appearance.
Test elongate, ovoid to triangular in outline, biserial chambers.
Test elongate ovate to subcylindrical, triserially arranged chambers, distinct septa.
Lenticular biconvex test, commonly with a few to many heavy and blunt to splayed or bifurcating radial spines.
Elongate test, lituoline in form with rounded periphery and biserial chambers, coiled in early stage and later uncoiled.
Test commonly attached to a substrate, trochospiral and planoconvex.
Test in a low trochospiral coil, spiral side flattened but slightly involute, final whorl slightly elevated and partly overlapping the preceding one.
Large circular test, centrally umbonate and narrowed at the periphery. Annular chambers subdivided into chamberlets.
Test planispiral, bilaterally symmetrical; sutural canal system opens into a single row of pores; septal bridges usually hollow and contain a retral process; aperture a series of large circular pores at base of aperture face.
Test short, subcylindrical, circular in section, base broadly rounded, chambers trochospirally arranged.
Ovate test, circular in section, triserial, with rapidly enlarging and strongly overlapping inflated chambers.
Globular to lenticular test,biserial enrolled chambers, periphery rounded to acute or carinate.
Planispiral test, bilaterally symmetrical, sutures radial, slightly curved, deeply incised near the umbilicus.
Involute to evolute test, centrally thickened, chambers divided into chamberlets.
Discoidal test, very low trochospiral to nearly planispiral, semieevolute on both sides.
Single or compound umbilical plug, aperture restricted by a toothplate that protrudes with a free edge into the aperture and forms an umbilical spiral canal.
Low trochospiral test, slightly compressed, rounded periphery, spiral side partially evolute around an umbonal boss, umbilical side involute, chambers with flaplike projections overhanging the umbilicus.
Globular test, lenticular or discoidal,planispirally enrolled.
Test planispiral and evolute, flattened, numerous narrow chambers in many rapidly expanding whorls, sutures strongly curved back at the periphery.
Smooth exterior, undivided chambers. External similarities in shape to N. venosus but is distinguished by the latter by the possession of trabeculae. Thick lenticular central part and flat final chambers in large individuals.
Lenticular, low trochospiral test, spiral side evolute with three slowly enlarging whorls, four to five chambers in the final whorl, umbilical side involute.
Planispirally, semi-involute to evolute coiled test, incomplete division of chambers into chamberlets.
Test planispiral, semi-involute to evolute, complete division of chambers into chamberlets.
Test globular to slightly depressed, planispiral and involute; aperture a narrow interiomarginal crescentic slit.
Trochospiral test with rapidly enlarging chambers, central aperture on umbilical side.
Large globular test with slightly projecting spines or tubercles.
Elongate test, sharply triangular in section and early stage triserial, later uniserial and rectangular. Aperture surrounded by a low collar.
Elongate test, rounded in section, triserial, surface with longitudinal costae or striae.
Test elongate, early stage triserial, later biserial. Chambers slightly inflated and strongly over-lapping, final pair comprising about two-thirds the test length, lower margin of chambers with numerous narrow bridgelike projections that cross the slightly constricted sutures; wall calcareous, finely perforate. Aperture an oblique loop in the apertural face, provided with a reduced toothplate that commences near the previous foramen and attaches to the lower part of the chamber wall, continuing to the lower border of the aperture, wjth supplementary sutural openings between the sutural bridges.