228 



irregular, but sufficiently definite to deserve mention. This large noass 

 of vacuoles is usually in contact with the . nucleus and sometimes com- 

 pletely envelopes it. When the vacuoles are thus aggregated, the 

 remainder of the cytoplasm is almost entirely free from them. The 

 contents of these vacuoles stain faintly in cold Sudan III. 



c t o p u s r u g o s u s is the common Octopus at Bermuda. There was 

 no difficulty in dissecting out the nerve cells, which in many instances 

 were completely isolated. In the living .cell the cytoplasm is compact 



and uniform in texture. 

 The spherules are a light 

 olive green tending to- 

 ward yellow; while some 

 of them are scattered 

 sparsely through the cyto- 

 plasm, there is usually 

 some one place where 

 they are so crowded and 

 massed as to form the 

 most conspicuous feature 

 of the cell. There is 

 no constancy in their 

 position in the cyto- 

 plasm nor in the size or shape of the mass formed by them. 



Gaeiaeff^) (p. 155) finds in Octopus vulgaris two distinct regions 

 in the cytoplasm. "Daraus folgt, daß die Ganglienzelle aus zwei 

 Schichten zusammengesetzt ist, aus einer äußeren und einer inneren, 

 welche ihrer Struktur nach scharf voneinander abweichen. Die äußere 

 Schicht werden wir Exoplasma oder Hyaloplasma, die innere Endo- 

 plasma nennen." The sketches in which this diöerentiation is shown 

 look much like some of our preparations. We have also noticed that 

 the cytoplasm is penetrated by processes, the so-called Saftkanälchen; 

 but the outer layer does not seem to us to be a primary part of the 

 cells; it seems rather to be a secondary acquisition. If this outer 

 layer is an intrinsic part of the unit structure of the nerve cell, it 

 seems very strange that the living cells can be so readily dissected 

 out without showing it. Gariaeff's figs. 4, 7 and 9 seem to us to 

 indicate that this exoplasm is composed of neuroglia cells and the 

 nuclei of Schwann's sheath. If such proves to be the true inter- 



1) Wl. Gariaeff, Zur Histologie des zentralen Nervensystems der 

 Cephalopoden. I. Subösophagealganglienmasse von Octopus vulgaris. 

 Zeitschr. f. wiss. Zool., Bd. 92, pp. 149—186, Taf. 9, 10. 



Fig. 2. Octopus rugosus. A camera lucida 

 drawing of a living ganglion cell showing the vacuoles 

 near the upper surface (the only ones drawn). 1 inch 

 ocular and ^/^j inch homog. immersion objective. 



I 



