THE FAMILY GLOBIGERINIDiE 205 



certain forms of the next family, the Rotaliid.e, as 

 Glohigerina cretacea and Dlscorhina riigosa. 



Genus Glohigerina, D'Orbigny. 



Test coarsely perforate ; trochoid, rotaliform, or 

 symmetrically planospiral ; segments few, inflated ; 

 pelagic specimens spinous. Camhriaii to Beceiif. 



Examples. — G. buUoides, D'Orbigny, 'Ann. Sci. 

 Nat.' vol. vii. 1826, p. 277, No. 1 ; ' Modeles,' Xo. 17 

 and No. 76. 



The size of the test in this species varies greatly. 

 The British specimens are usually one-fifth the dia- 

 meter of good typical examples from mid-ocean. 

 It is found in every sea, and certain deep-sea 

 deposits are often chiefly composed of the shells of 

 this type-form. Undoubted examples are recorded 

 from strata of Lower Cretaceous age, and it is 

 well distributed throughout almost all Tertiary de- 

 posits up to the present time. The Pliocene speci- 

 mens more nearly approach the recent examples 

 in point of size. 



Fig. H shows the appearance of the test when 

 obtained from bottom oceanic deposits. (Plate 11, 

 figs. H, //.) 



G. bulloides, var. triloba, Reuss, ' Denkschr. d. k. 

 Akad. Wiss. Wien,' vol. i. 1849, p. 374, pi. xlvii. 

 fig. 11 a-e. 



This is a three-chambered variety with an almost 

 invisible spire, which is found associated with the 

 typical G. h/illoides. Fig. G represents a surface 



