2^7 



to the body of the cell, the axon being practically free from them. These 

 bodies stain quickly in Sudan III or in Neutral red and they are turned 

 black in any of the fixing mixtures containing osmic acid, such as 

 Hermann's or Flemming's fluids. These three tests indicate that 

 these bodies are of a fatty nature and agree with our previous ob- 

 servations on Limax and Planorbis. It is quite usual to find the nuc- 

 leus deeply indented on one surface, a condition which we discussed 

 in our first paper (1908) and believe to be related to the metabolic 

 activity of the nucleus. 



Dolabriferavirens. This tectibranch is commonly found on stones 

 at low tide and is quite abundant in Hungry Bay. The living nerve 

 cells are much smaller than those of Chromodoris zebra. The cyto- 

 plasm is full of minute, closely packed vacuoles, the contents of which 

 stain with Sudan III. In a few cells there was a mass of greenish 

 pigment in the region of the origin of the axon. This pigment is 

 distinct from the minute vacuoles; it quickly diffuses in alcohol. In 

 Chromodoris and Octopus the pigment is much more abundant than 

 in Dolabrifera. A mass of living nerve cells of the latter have a 

 whitish appearance, while in the other two species the coloring is 

 so conspicuous as to be noticed at once. 



The Mangrove Snail. This brackish-water snail lives on the 

 mangrove trees. The cytoplasm of the nerve cells is faintly tinted 

 with yellowish, owing to the presence of pigment in minute granules. 

 All through the cytoplasm are also found numerous small bodies 



which, though of 



deeper hue, have the 

 same general color 

 as the granules. 

 We believe these to 

 be metabolic bodies 

 similar in function 

 to those described 

 above. 



Strombus gi- 

 gas. This is the 

 large whelk com- 

 mon in the waters 

 about Bermuda. The 



living unstained nerve cell is almost colorless, and the numerous 

 vacuoles usually have a characteristic arrangement (Fig. 1). In many 

 cells the vacuoles were found collected into a spheroidal mass, often 



15* 



Fig. 1. Strombus gigas. Living nerve cell with neuron. 

 The vacuoles are collected in one mass. The contents of the 

 vacuoles react quickly to warm Sudan III. 1 inch ocular 

 and */jo inch homog. immersion objective. 



