458 Mr. R. Kiikpatiick on the Structure of 



Note 11. — The umbilicus of each Numniulitid shell or coil 

 of Eozoon corresponds to the afstrorhiza of Stromatoporoids. 

 The umbilicus is funnel-shaped, being broad at the proximal 

 end and reduced to a small pore at the distal. To obtain in 

 Eozoon the same appearance as is seen on the surface of 

 Stromatopora it is necessary to cut a vertical section in the 

 plane of the flat surfaces of the Nummulitid shells. In 

 Eozoon each coil would be found to be small and surrounded 

 by a zone of supplementary de])Osit. The dark radial streaks 

 of the astrorhizaj of Strouiatcporoids are probably the ex[)res- 

 sion of the thick masses of sarcode (? with iron) in the grooves 

 between surface-tubercles of the coils of chambers. 



Note 12. — Possibly the little " buds " seen on the Nummu- 

 litid shells of Eozoon may result from a process of agamouony. 

 See the beautiful figures of Peneroplis pertusus in F. VV. 

 Winter's remarkable study of the Thalamophoren (^ Pro- 

 tistenkunde,' x. 1907, p. 1, pi. i. fig. 1). Probably tl.iu 

 sections of Eozoon will reveal some very interesting fact.-:. 



Note 13. — The rouleaux of Numniulitid shells are serpentine 

 in a double sense. The existence in Eozoon of bands of 

 dolomite or secondary calcite alternating with bauds of 

 olivine or serpentine results, I think^ from the following 

 causes : — The supplementary skeleton (calcite or dolomite) 

 originally formed masses of pure calcite with very little 

 protoplasm in it, but the coils of shells were full of proto- 

 plasm containing metallic compounds. There would be a 

 great difference in the molecular changes and affinities in the 

 primary and secondary skeletons^ and in the former the silica 

 would much more easily combine with the iron-magnesian 

 compounds to form olivine. The reasonableness of this theory 

 is shown by the fact that the canal-system permeatiiig the 

 secondary skeleton is wonderfully preserved m olivine and 

 can be etched out by dissolving the calcite. 



Eozoon may be regarded as a marvellous nature-print by 

 Nature herself, and one beside which the most retined products 

 of human art are clumsy, for the finest details of the 

 structure of the skeleton have been preserved. During each 

 " process '^ the parts have been changed molecule by molecule. 

 It is true the resulting work of "art" has been woefully 

 damaged in the case oi Eozoon vesuvii, E. bavancum, &c. by 

 later rough treatment, such as heat, pressure, and cruni|iling. 



In E. vesuvii the extra baking has converted the olivine 

 into a serpentine almost resembling tha granular C/Ornish 

 kind^ but the original Nun)muiitid pattern is still obvious. 



