THE FAMILY EOTALIIDiE 2L5 



POEIN.E embrace a number of somewhat aberrant 

 forms, which, although in their earhest chambers 

 distinctly rotaline, are sooner or later modifiecl in 

 their plan of growth, and increase in size by the 

 addition of numerous chamberlets, somewhat ir- 

 regularly disposed in relation to one another (acer- 

 vuline). 



Suh-fainili/'V. Spirillinin.e. 

 Test spiral, non-septate. 



Genus Sjnrillina, Ehrenberg. 



Test a complanate, piano-spiral, or conoidal non- 

 septate tube ; free or attached. ZJpj^e)- Cnmhrian to 

 Recent. 



Example. — S. vivipara, Ehrenberg, ' Abhandl. k. 

 Akad. Wiss.' Berlin, 1841, p. 442, pi. iii. fig. 41. 



This is a delicate little species, usually free but 

 sometimes found attached to marine objects, as sea- 

 weed. It is very extensively distributed, and occurs 

 usually in fine muddy deposits of less than 150 

 fathoms. As a fossil it has been noted from various 

 strata dating from Miocene times. Miocene to Becent. 

 (Plate 12, fig. A.) 



Sub-faniihj 2. Eotalhn.e. 



Test spiral, Rotaliform, rarely evolute, very rarely 

 irregular or acervuline. 



