THE FAMILY MILIOLID^ 101 



{Ndiitllus), 'Test. MicT.' 1798, pp. 112, 113, 115, pis. 

 xxi.-xxiii. 



The single species of this genus is found com- 

 monly in the West Indies, the Red Sea, and the 

 Indian Ocean. It is found at moderate depths. 

 Miocene to Becent. (Plate 4, figs. E, e.) 



The sub-generic type Meandrojjsina (Munier 

 Chalmas) has a test in which the median layer of 

 chamberlets is arranged as in Orhiculijia, whilst 

 the outer layers are formed on the plan of 

 Orhitolites. 



Genus Orhitolites, Lamaeck. 



Test discoidal, sometimes undulate or rarely 

 sinuous ; growth either spiral (non-embracing) just 

 at the commencement, or with one or more inflated 

 primordial chambers ; subsequently cyclical ; cham- 

 bers more or less regularly divided into chamberlets. 

 Upper Cretaceous to Becetit. 



Example. — 0. fo;;?^;/rn?r//c^ Lamarck, ' Syst. Anim. 

 sans Vert.' p. 87G ; Carpenter, 'Phil. Trans.' 1856, 

 p. 224, pis. iv.-ix. 



This is one of the best known species of Fora- 

 minifera, for they form a large proportion of the 

 calcareous sands which make the beaches, and assist 

 in the building up of the coral islands of the Pacific 

 and Indian Oceans. It is connnon in all tropical 

 and temperate seas, occurring abundantly in the 

 shallow-water sands. 



0. complanata is the most complex species of the 



