NERVE CELLS OF THE CRAYFISH 43 
and Homarus, comparing them with corresponding elements in 
insect and mammalian ganglion cells. Monti’s figures are the 
only ones which give Golgi apparatus pictures of arthropod cells 
which resemble those of other forms, and we may assume that 
the preparations of other workers were incomplete or unreliable 
so far as this cytoplasmic structure is concerned. It seems that 
in these forms the apparatus is very delicate and that there is 
less tendency toward reticular formation than in vertebrate 
nerve cells. In addition to the diffuse Golgi apparatus, Monti 
discovered in the small ganglion cells of young Crustacea pre- 
pared by the Golgi method, a minute tightly wound skein of 
threads at one side of the nucleus which is directly comparable in 
appearance and position with the ‘centrophormien’ of Ballowitz 
or the Holmgren ‘canals’ as they appear in non-nervous cells. 
Monti reaches the conclusion that in the invertebrates a 
portion of the ‘chondrioma,’ i.e., the mitochondrial granulation 
as a whole, becomes the Golgi apparatus and the remainder 
disappears. ‘This conclusion is based merely on the superficial 
resemblance between the thick Golgi (arsenious acid-silver) 
preparations and thin sections stained to show mitochondria. 
Yet the lack of evidence for such a deduction should not detract 
from the great value of her morphological contributions. Un- 
fortunately for the present purpose, she did not obtain any 
satisfactory preparations of the large nerve cells of either Astacus 
or Homarus, so her figures cannot be compared directly with 
those presented in this paper. 
Tello (14) describes a cell in the electric lobe of the brain 
of the torpedo in which there is in Cajal preparations an intra- 
cellular axone almost identical in appearance with that of the 
crayfish. His‘text-figure 19 would serve as a figure of the cray- 
fish nerve cell were it not for the presence of a dendrite and of a 
fibrillar capsule about the nucleus. Because of the closeness of 
this similarity I give the translation of a part of his description: 
As may be seen in figures 19 and 20, the nerve cells of the lobe men- 
tioned (bulb of ray and torpedo) possess a very complicated reticula- 
tion. Immediately beneath the membrane lies a dense layer of rather 
coarse primary filaments arranged in bundles parallel and plexiform, 
