CALCARINA. FORAMENIFERA. 25 
TRIBE V.— LITUOLACEA. 
Shell partially spiral, the last volutions continued in a 
straight line. 
Genus XII. — LITUOLA. — Lamarck. 
Generic Character. — Shell multilocular, partially spiral, 
and disciform, with contiguous volutions, the last terminat- 
ing in a straight line; cells irregular, septa transverse and 
simple; the last perforated by from three to six holes. 
Lituola difformis. Plate ILI. fig. 4, and plate II. fig. 30. 
Genus XIII.— SPIROLINA. — Lamarck. 
Generic Character. — Shell multilocular, partially spiral, 
and disciform, with contiguous volutions, the last terminat- 
ing in a straight line; septa transverse, perforated by a 
tube. 
Spirolina stenostoma. Plate II. figs. 33. and 35. 
TRIBE VI.— HIPPURANA. 
Shells straight, or nearly so. 
Genus XI1V.— CLAVULINA. — D’Orbigny. 
Generic Character. — Shell multilocular, straight, club- 
shaped, compressed. 
Clavulina corruguta. Plate II. figs. 43, 44. 
Genus XV.— HIPPURITES. — Lamarck. 
Generic Character. — Shell cylindraceo-conical, straight, 
or slightly arcuated ; multilocular, with transverse septa ; 
provided with an internal lateral channel, formed by two 
parallel, longitudinal, obtuse, convergent ridges, the last 
closed by an operculum. 
Hippurites Infundibluiformis. Plate II. fig. 36. 
De Blainville considers this asa bivalve, and places it in the family Rudistis ; 
but we consider its character too imperfectly known to warrant our placing it 
in that tribe. 
Genus XVI.— CALCARINA. — D’ Orbigny. 
Generic Character.—Shell a double cone, radiated above, 
the radii spinous. 
Calcarina rarispina. Plate II. figs. 45, 46. 
