288 CLASS V. CEPHALOPODA. ORDER I. POLYTHALAMIA, 
may, however, we cannot but feel interested in the meritorious expo- 
sition which has been made by D’Orbigny after an examination of many 
hundred species, and have therefore chosen to exhibit his arrange- 
ment. 
The Foraminifera are divided by D’Orbigny into five sections of fifty- 
two genera, according to their conceived affinities of structure ; and we 
have selected the typical one of each as sufficient, under existing circum- 
stances, for their methodical distribution. 
OrBICULINA. TEXTULARIA. 
SPIROLOCULINA. Noposaria. 
PoLYSTOMELLA. 
ORBICULINA, Lamarck. 
Testa orbicularis, subdiscoidea, spiralis, spira excentrica ; loculis in cavi- 
tates parvulas divisis ; orificio unico. aut perpluribus. 
To this genus we propose to refer all the so-called foraminiferous cepha- 
lopods that are included by D’Orbigny in his family of Les Entomosteques, 
containing the following five genera: Amphistegina, Heterostegina, Orbi- 
culina, Alveolina and Fabularia. In the first two of these divisions the 
shell is characterized as having only a single orifice in it, but in the 
remainder it is said to exhibit a number of much smaller openings ; 
Deshayes divides them into sections accordingly, but we refrain from 
entering more minutely into the subdivision of these microscopic bodies 
until the zoological relation which is assigned to them has been clearly 
and credibly confirmed. 
Kzamples. 
Pl. CCXCVII. Fig. 1. 
OrBICULINA UNIvERSA, D’Orbigny, Mollusques des Iles Canaries, Fora- 
miniféres, pl. 1. f. 1. 
