29^ 



NATURE 



{jfttly 24, 1879 



In the centre of the larger figure we see the globular | germ-chamber of the animal (Ka) round which the next 









2 



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^<milLllJJ>^ 



Fig. 13. 



following chambers (K) are spirally arranged. Then in 

 four directions curved rows of chambers (K) are formed, 

 which are separated by intermediate matter (Z). The 

 chambers communicate with each other, partly by round 

 passages (G), partly by pore-canals (P). Through the 

 intermediary matter (Z) a canal-system is extended, 

 ■which in the long arms of the shell ends in many 

 minute canals opening to the surface (K/). Through 

 the pores of these little canals, as well as through 

 the orifices of the peripheric pore-canals (P) of the 

 •outer rows of chambers, the sarcode, i.e., the gela- 

 tinous body-substance of the animals, is in commu- 

 nication with the outside. In some parts protruded, 

 granular sarcode filaments are represented (S, S); these 

 are the so-called pseudopodia. At C we see two chitinous 

 ■chamber-linings with adherent linings of pore-canals, 

 magnified 350 times ; at d are drawn chitinous ducts 

 from the canal-system in the intermediary matter, also 

 magnified 350 times, and freed from lime by treat- 

 iment with dilute chromic acid. Fig. 13 represents a 

 small part of a cross section of a tertiary Nuimnidina, 

 magnified 220 times. K K are the chambers which were 

 .filled with sarcode. The superposed chambers communi- 

 cate by means of pore-canals (P P). Between the cham- 

 bers there is a deposit of poreless intermediary matter (Z). 

 into which ramified canals are penetrating. Fig. 14 shows 

 .five pore-canals, magnified 500 times. Here it is seen dis- 

 tinctly that they are round tubes separated by calcareous 

 matter. Some of them are partly filled with a dark 

 •material. 



According to Dawson and Carpenter the limestone of 

 the Eozoon represents the shell of the Eozoon animal, and 

 the serpentine the material filling the chambers. Thus 

 ■the serpentine now takes the place of the sarcode which 

 ■once lived in these chambers, and which from its sub- 

 stance secreted the lime as a shell. The serpentine 

 patches of the fossil Eozoon, according to this view, have 

 the same shape and size which the separate chamber 

 bodies of the living animal possessed when fully ex- 

 tended. 



The separate fibres of the bands lying between the lime- 

 stone and the serpentine, according to Dawson and Car- 

 penter, are the siliceous fillings of the minute canals 

 •through which the sarcode body could send pseudopodia- 



FlG, 14, 



Fig. is. 



filaments into the water outside of the shell. The simple 



Fig. 16. 



and the ramified stems in the limestone are siliceous 



