282 M. Otto Halm on Eozoon canadense. 



present it cannot be mistaken by the geologist. But even as 

 to this shell the zoologists underwent a dece'ptio visas. 



The serpentine mass is always round. If a chamber be cut 

 in any way except equatorially, the limestone mass of course 

 projects over the serpentine mass, and the one shines through 

 the other ; the inner angle of section now projects itself as a 

 line upon the surface of section ; and thus is produced the ap- 

 pearance of a shellj especially if asbestos needles are seated 

 upon the margin of the limestone, and partially project beyond 

 it. We may easily convince oui selves of the illusion at 

 sinuations of the serpentine mass, as also in purely equatorial 

 sections. 



Chrysotile layers are to be found in every serpentine. The 

 weathering of serpentine takes place in divisions ; and hence 

 the delusive walls. 



How, it must further be asked, should a canal-system make 

 a dead stop before a crystalline individual? If the calcareous 

 shell were originally there, the canal-systems must have tra- 

 versed it in accordance with the law of organic structure. If 

 crystal-formation, or any other condition which destroyed the 

 canal-systems, afterwards occurred, this altered nothing in the 

 original arrangement of the canal-systems ; they could at the 

 utmost disappear here and there, and, indeed, in separate crys- 

 talline individuals, but must have been continued in the next 

 individual. But there is nothing of this hind. The separate 

 systems are rather completely limited in crystalline individuals, 

 from which it follows that the crystalline mass, nay, the lime- 

 stone, was in existence before the canal-system. These crys- 

 talline individuals are only commencements of crystal-forma- 

 tion. And finally we must ask wdiy are there never canal- 

 systems in twin crystals? For the simple reason that these 

 had become hard, while the other parts were still soft. 



As a last thing I will notice how improbable was the pre- 

 servation of the structures in the rock wdiich bears in it such 

 distinct traces of having suffered violence. 



I fancy from these statements of fact that the Eozoon, after 

 a brief but brilliant existence, is buried. It was indeed a 

 " dawn animal." 



In conclusion, I offer my honoured teacher Pruf. von 

 Quenstedt, of Tubingen, and Dr. von Hochstetter, of Vienna, 

 my best thanks for the liberality with which they have fur- 

 nished me with material for my investigation. Nor can I 

 omit to commend the admirable thin rock-sections of Mr. R. 

 Fues, of Berlin. 



My investigations were made with an excellent new 

 Hartnack's instrument (VII. a), and witli an English one by 

 Baker, of Ijondon. 



