838 MICROSCOPIC FORMS OF ANIMAL LIFE 



who at once recognised its foraminiferal nature, 1 the calcareous 

 layers presenting the characteristic appearances of true shell, so dis- 

 posed as to form an irregularly chambered structure, and frequently 

 traversed by systems of ramifying canals corresponding to those of 

 Calcarina ; whilst the serpentinous or other silicious layers were 

 regarded by him as having been formed by the infiltration of sili- 

 cates in solution into the cavities originally occupied by the sarcode- 

 body of the animal a process of whose occurrence at various geo- 

 logical periods, and also at the present time, abundant evidence has 

 already been adduced. Having himself taken up the investigation 

 (at the instance of Sir William Logan), the Author was not only able 

 to confirm Dr. Dawson's conclusions, but to adduce new and im- 

 portant evidence in support of them. 2 Although this determination 

 has been called in question, on the ground that some resemblance to 

 the supposed organic structure of Eozoon is presented by bodies of 

 purely mineral origin, 3 yet, as it lias been accepted not only by most 

 of those whose knowledge of foraminiferal structure gives weight to 

 their judgment (among whom the late Professor Max Schultze may 

 be specially named), but also by geologists who have specially 

 studied the micro-mineralogical structure of the older Metamorphic 

 rocks, 4 the Author feels justified in here describing Eozoon as 

 he believes it to have existed when it originally extended itself as 

 an animal growth over vast areas of the sea-bottom in the Laurent inn 

 epoch. 



Whilst essentially belonging to the Nummuline group, in virtue 

 of the fine tubulation of the shelly layers forming the ' proper wall ' 

 of its chambers, Eozoon is related to various types of recent Forti- 

 minifera in its other characters. For in its indeterminate zoophytic 

 mode of growth it agrees with Polytrema in the incomplete separa- 

 tion of its chambers ; it has its parallel in Carpentaria ; whilst in the 

 high development of its ' intermediate skeleton ' and of the ' canal 

 system ' by which this is formed and nourished, it finds its nearest 

 representative in Calcarina. Its calcareous layers were so super- 

 posed one upon another as to include between them a succession 



1 This recognition was due, as Dr. Dawson has explicitly stated in his original 

 memoir (Quart. Journ. of Geol. Soc. vol. xxi. p54), to his acquaintance, not merely 

 with the Author's previous researches on the minute structure of the Foramiiiifera, 

 but with the special characters presented by thin sections of Calcarina which had 

 been transmitted to him by the Author. Dr. Dawson has given an account of the 

 geological and mineral ogical relations of Eozoon, as well as of its organic structure, in 

 a small book entitled The Dawn of Life. 



2 For a fuller account of the results of the Author's own study of Eozoon, and of the 

 basis on which the above reconstruction is founded, see his papers in Quart. Journ. 

 of Geol. Soc. vol. xxi. p. 59, and vol. xxii. p. 219, and in the Intellectual Observer, 

 vol. vii. 1865, p. 278 ; and his ' Further Researches ' in Ann. of Nat. Hist. June 1874. 



5 See the memoirs of Professors King and Rowney in Quart. Journ. of Geol. Soc. 

 vol. xxii. p. 185, &nd.Ann. of Nat. Hist. May 1874. 



4 Among these the Author is permitted to mention Professor Geikie, of Edinburgh, 

 who has thus studied the older rocks of Scotland, and Professor Bonney of London, who 

 has made a like study of the Cornish and other Serpentines. By both these eminent 

 authorities he is assured that they have met with no purely mineral structure in the 

 least resembling Eozoon, either in its regular alternation of calcareous and serpen- 

 tinous lamellae, or in the dendritic extensions of the latter into the former ; and while 

 they accept as entirely satisfactory the doctrine of its organic origin maintained by 

 the Author, they find themselves unable to conceive of any inorganic agency by which 

 such a structure could have been produced. 



