308 APPENDIX 



tubulated very finely. Intermediate skeleton largely 

 developed, especially at the lower part, and traversed 

 by large branching canals, often with smaller canals 

 in their interstices. Lower laminae and chambers 

 often three millimetres in thickness. Upper laminae 

 and chambers one millimetre or less. Age Upper 

 Laurentian and perhaps Huronian. 



Var. MINOR. — Supplemental skeleton wanting, 

 except near the base, and with very fine canals. 

 Laminae of sarcode much mammillated, thin, and 

 separated by very thin walls. Probably a depauper- 

 ated variety. 



Var. ACERVULINA. — In oval or rounded masses, 

 wholly acervuline. Cells rounded ; intermediate 

 skeleton absent or much reduced ; cell-walls tubu- 

 lated. This may be a distinct species, but it closely 

 resembles the acervuline parts of the ordinary form. 



Assuming the Archseospherinae so abundantly 

 found in the Eozoon limestones to be distinct 

 organisms, and not mere germs or buds of Eozoon, 

 they may be thus defined : — 



Genus Arch^ospherina, Dawson. 

 A provisional genus, to include rounded solitary 

 chambers, or globigerine assemblages of such cham- 



