No. 4.] DAWSON — EOZOON CANADENSE. 239 



and they sometimes present the curious character that they are 

 hollow vesicles of serpentine filled with calcite, and when these 

 have been cut across in making a section, and the calcite has 

 been dissolved out with an acid, they present very singular ap- 

 pearances. They may in some cases have been germs oi' Eozoon, 

 or smaller foraminifera of the type of Archceosphei^ince, ovGr^rrown 

 by the calcareous walls. It is farther to be observed, as I have 

 also elsewhere remarked, that the serpentine filling the larger 

 spaces between the calcareous laminae sometimes shows indica- 

 tions of deposit as a lining of the cells, and in some specimens 

 this lining has not filled the original space but has left a drusy 

 cavity afterwards filled with calcite. 



Again, in parts of the canal system, especially when filled with 

 dolomite, there occur little disc-like bodies or trumpet-shaped 

 terminations of canals. These, I fancy, are the calyx-like objects 

 figured by Hahn. Their precise significance is not known, 

 further than that they may represent the expanded ends of 

 canals. Another appearance deserviug of notice is the occurrence 

 of portions of specimens of Eozoon in which little or no serpentine 

 occupies the chambers. In this case the laminae have either 

 been pressed close together, or the chambers have been filled with 

 calcite not distinguishable from the walls, in which, however, the 

 casts of groups of canals often occur, and might then be more 

 readily mistaken for algae than when they occur between laminae 

 of serpentine. 



Lastly, I have recently found in a specimen of Eozoon, struc- 

 tures which may possibly indicate contemporaneous plants. I 

 have previously remarked the occurrence of deep pits or cylindri- 

 cal cavities in some specimens of Eozoon, and have supposed that 

 they might be of the nature of oscula. Those now referred to 

 are, however, more definite than any previously observed. They 

 are cylindrical perforations penetrating the whole thickness of 

 the mass, and filled with calcite. One of them is simple, another 

 seems to bifurcate. They are about an eighth of an inch in 

 diameter, and present indications of alternate swellings and con- 

 tractions. In approaching them the plates of serpentine split 

 into two, and then unite, forming a continuous close wall of 

 sarc.ode. This proves that these tubes are not perforations of 

 any boring animals. They must be either definite canals pene- 

 tratiag the mass while living, or must represent cylindrical stems 

 of algae or other perishable organisms, around which the Eozoon 



