104 



NATURE STUDY IN SCHOOLS. 



limestones also have had a similar origin. Indeed, far back among the oldest 

 Archaic rocks, among the Serpentine limestones of that first land which was 

 pushed up from the bed of the primitive ocean, the Canadian Laurentian, we 

 find that the earliest remains of animal life yet discovered, the Eozoon cana- 

 dense, was a foraminifeia. 



It is singular that while many higher and larger forms of animal life 

 have passed away leaving their fossil remains or some distant living relatives 

 only to tell of their former existence, some of the most primitive, minute and 

 simple forms of life should remain represented by species which are closely 



Fig. 55. 



Baliana Foraminifera greatly enlarged. 



alliel in form and method of living to those w hich were in existence uncount- 

 ed ages ago. 



Some of the most easily accessible of the shell bearing foraminifera now 

 living can be found in the shallow waters of the Bahama islands. One form, 

 bright reddish purple in color, the ruby loraminifera, occurs clinging in round- 

 ed masses to the base of coral. Another, which is typical in form, occurs 

 free, as flattened disks of varying forms, but in the adult state very nearly 

 round. This disk is perforated by a rather regular set of minute holes through 

 which the animal thrusts its jelly-like arms. See fig. 55. This is the Ba- 

 hama foraminifera ( Orbitulina adunca ) and is greedily eaten by two or three 

 species of echinoderm. 



Shells of different species of foraminifera are exceedingly variable in form, 

 some being globular, some globular with other globes attached to them, form- 

 ing grape-like clusters. A common form is a shell with chambers, not unlike 

 that of the chambered nautilus. 



