484 On the Nervous Systems of 
mals, insects and worms: In which case these, 
animals would have no spinal marrow, and the 
absence. of this medullary production would: be 
the common character of all the animals with 
white blood.’’* 
The second includes some Mollusca, which have 
a brain and nerves passing off. from it in @ 
radiated manner, but no elongation of the brainy 
analogous to the spinal marrow.of the fortner 
order. There are however scattered ganglions, 
almost as large as the brain itself,t in various 
parts of the body. 
The third comprehends those animals, which: 
are of a gelatinous texture and have no evident 
nervous system as many Zoophytes, or Polypes. 
In these nothing corresponding. to brain, spinab 
Marrow, or nerves, can be discovered; nor cam 
vessels or muscular fibres even be detected. t 
Thus we find, as we descend in the scale of 
animal creation, the common trunk of the ner~ 
vous system gradually lessening and the medullary 
* Anatomie Comparée T. II. p. 124. 
+ Ibid. p. 9. ’ 
+ “ La faculté de sentir & celle de se contracter, qui 
dans la plupart des animaux sont exclusivement propres, 
Yune 4 la substance nerveuse & |’ autre a la fibre charnue, 
paroissent étre également répandues dans toutes les parties 
de certains animaux gélatineux, dans lesquels on n’ ap- 
percoit ni fibres ni nerfs.” Cuvier Anat. Comp, T. I, pr 27« 
