204 THE FOEAMINIFEEA 



CHAPTEE XIV 

 THE FAMILY GLOBIGEEINIDiE 



The group of Foraminifera which constitutes the. 

 above family is not, hke most of the preceding 

 divisions, separable into a closely connected and pro- 

 gressive series of forms, but the various genera have 

 many features in common with the whole group, and 

 the phenomena of isomorphism amongst species of 

 different genera is often very marked. The greater 

 number of the members of the Globigeeinid.e are 

 pelagic or surface-living organisms. 



The salient characters of the group are a test 

 which is never attached ; a perforate shell-wall very 

 variable in thickness even in the same genus ; 

 chambers few, inflated, arranged spirally ; aperture 

 single or multiple, conspicuous. There is no supple- 

 mentary skeleton nor canal system. 



With regard to the isomorphism of the various 

 species, mention maybe made of Glohigerina hulloicles 

 with Candeina iiitlda, Glohigerina cunglohata with 

 Sj^lKpyoidina hulloides and Pullenia ohliquiloculata 

 and Glohigeyina aq^uilateralis with Hastigerina j^ela- 

 gica and Pullenia quinqueloha. The genus Glohigerina 

 has some isomorphous types corresponding even with 



