Stromatoporoids and of Eozoon. 451 



Accoiclinglj Eozoon canadense is a colonial Perforate 

 Forauiiniferan, eacli unit being a coiled shell of tlieNummu- 

 litid type. There are no alar prolongations as in XiwunuUtes *. 



Classification of Stromatoporoids. 



Tiie current classification, that of Nicholson, is based on 

 the theory that Stromatoporoids are Hydrozoa, and naturally 

 needs revision. My work is not sufficiently advanced to 

 enable me to make any other than a few general remark?. 



The first point to notice is that these ancient Foraminifera 

 are all colonial forms which frequently form massive blocks. 



Murchison and Lindstrom mention the thick strata, the 

 pillars, and huge balls composed mainly of Stromatopora 

 di^coidea to be found at Gothland, and Dupont calls atten- 

 tion to the fact that these organisms enter largely into the 

 formation of the Devonian limestones of Belgium. The 

 Stromatoporoids and Eozoon were, in fact, reef-forming 

 Foraminifern. 



These colonies of Foraminifera represent a simpler type 

 than is found at present, when most of the Foraminifera exist 

 as separate individuals, though it is not improbable that some 

 of the larger modern Foraminifera may be true colonies, and 

 not merely individuals which have grown by extension of 

 single segments in vertical and horizontal directions. 



1 believe Eozoon to be the ancestor o£ the Nummulitidce 

 and the Stromatoporoids to be the predecessors of some of the 

 spirilline, rotalian, and acervuliiie llotaliiJ^. 



In fitting these primitive colonial Foraminifera into Brady's 

 system they should be placed at the head of their respective 

 families, viz. Eozooninte in the Nummulitidse, and Stromato- 

 porinse and Labechiinoe in the Rutaliidse. The colonial habit 

 is not of the first importance from the systematic point of 

 view. It is the unit wdiich gives the clu3 to the affinities. 

 Certainly the unit of Eozoon is a Nummulitid and that of 

 Stromatopora Rotalian. In Beatricea I see central globular 

 Globic/ei-ina-like chambers, but the general mode of growth 

 suggests the acervuline type common among the Ilotaliida\ 



Eozoon. Geological and Biological Implications. 



I find that Eozoonal specimens from N.W. Scotland, from 

 Comiemara, and from Central Europe (Prof. Giimbel) are 



* It may be pouited out, alar prolongations are only present in some 

 subfamilies of Xummulitidse, and not in all. 



