THE FAMILY MILIOLID^ 103 



Sub-family 5. Alveolinin.e. 



Test spiral, elongated in the line of the axis of 

 convolution, chambers divided into chamberlets. 



Genus Alveolina, Defeance. 



Test subgiobular, elliptical, or fusiform; recent 

 species often with subdivided chamberlets. Ci-e- 

 taceoua to Becenf. 



Example. — A. Boscii, Defrance sp. {Oryzaria)^ 

 ' Diet. Sci. Nat.' vol. xvi. 1820, p. 104. 



The chamberlets in this species are often sub- 

 divided by horizontal partitions, which give rise to a 

 complex series of pores, appearing externally along 

 the septal plane of the test. This species seems 

 restricted to shallow^ water, being rarely found deeper 

 than 30 fathoms. Middle Eocene to Becent. (Plate 

 4, figs. G, g.) 



The sub-genus Flosculina, Stache, is chiefly 

 distinguished by its extraordinarily thickened shell - 

 wall, the rows of chamberlets occupying a proportion- 

 ately small space. 



Genus Lacazina, Schlumbeegee. 



Test ovoid or subspherical ; the chambers 

 arranged in an elongated coil, as in Alveolina, but 

 having apertural communication alternately at 

 opposite ends. The chambers are subdivided into 

 chamberlets. Cretaceous and Tertiary. 



Example. — L. WicJniiairiii, Schlumberger, 'Bull. 



