496 
DR. W. H. RANSOM ON THE OYUM OF OSSEOUS FISHES. 
blood-corpuscle ; the lowest known existing organisms in the animal or vegetable king- 
dom, as the Amoebae ; the earliest ascertained traces of organic beings in the geological 
record, as the Eozoon Canadense , — are all essentially masses of protoplasm, and some of 
them have been shown to possess some important properties in common, as the researches 
of Kuhne* and M. Schulze f have shown. 
This cursory glance beyond the limited area which I have been hitherto examining, 
gives some support to a view, on other grounds probable, that the rhythmic contractions 
of the lower forms of protoplasm precede and lead up to the fissile movements which 
result in cell multiplication in the higher forms of protoplasm. Witness the amoeboid 
stages of some monads before they encyst and multiply by fission, as described by 
Cienkowski J. 
One is thus easily led to form the general conception that matter, in passing from the 
inorganic to the organic world, first takes on a homogeneous thick fluid form, the denser 
surface of which is endowed with a rhythmic contractility ; that it then is gradually con- 
verted into a higher form, which is granular, and contains fat, which loses its power of 
rhythmic contraction, and acquires that of dividing into separate masses by fission. 
Explanation of the Plates. 
PLATE XV. 
Diagram A. 
a. Dotted yelk-sac. 
h. Buttons. 
c. Micropyle. 
d. Inner sac indicated by the dark line (it should be in contact with the yelk-sac). 
e. e. Cortical layer, or matrix of the formative yelk, continuous with the inner surface of 
inner sac indicated by the fine shading. 
f. f. Yellow droplets and granules of the formative yelk imbedded in the cortical layer, 
and forming at its thicker portion the discus proligerus. 
g. Germinal vesicle with contents (introduced to show its position when last seen). 
h. Group of large store oil-drops. 
j. Food-yelk. 
Jc. Smaller oil-granules of the formative yelk. 
Figures 1 to 23 inclusive refer to eggs of Gasterosteus. 
Fig. 1. The unimpregnated egg, indented by pressure, viewed with a low power: — a, the 
micropyle (proportionally too large in the figure) ; b, the buttons ; c, oil-drops; 
d, the discus proligerus. 
* Loc. cit. t Das Protoplasma, 1863. 
+ “ Beitrage zur Keutniss der Monaden,” Archiv fur Mikroskopische Anatomie, 1865. 
