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 pei'iods, 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 minernl origin, 3 yet, as it has 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 m.-iy 

 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 Laurentian 

 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 Fora- 

 minifera in its other characters. For in its indeterminate zoophytic 

 mode of growth it agrees with Polytrema in the incomplete sep;n-;i 

 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. Jtnirtt. <>i' '.'</. .S'nr. vol. xxi. p. 541, to his acquaintance, not merely 

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

 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 Euziion, as well as of its organic structure, in 

 a small book entitled Tin- Dnirn nf Life. 



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

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

 nl' < ii ni . Sac. 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. nf .Y<</. ///.s/. -June ]S7I. 



" Sec the memoirs of Professors King and Knwiiey in Quart. Jo/ir/i. nf CcoL Soc. 

 vol. xxii. p. 185, and Ann. of Xut. llixl. .May 1*74. 



1 Among these the Author is permitted to mention L'rofessor Geikie, of Edinburgh, 

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

 has inii.de 11 like sludy of the Cornish and oilier Serpentines. By both these eminent 

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

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

 I i nous lamellie, or in the 1 dendril ie 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 unalile to eoneei\ cof any inorganic agency by which 

 such a structure could have been produced. 



