1 86 Journal of Comparative Neurology and Psychology. 



Fig. 2. 



conditions existing in these cells could be harmonized with other 

 mollusca. Clams just taken from the sea and those that had been 

 transported to Syracuse, N. Y., were used, but no constant differ- 

 ence was found to exist. The tissue was fixed in picric acid- 

 sublimate (Holmgren), as well as sublimate and osmic acid. 

 In Fig. 2 the cytoplasm is loosely granular, showing many 



fibers present in the region where the 

 axone arises. The nucleus is limited by 

 a conspicuously staining membrane; the 

 chromatin is pretty generally distrib- 

 uted throughout the nucleus. On one 

 side of the nucleus there is a cone- 

 shaped mass of deeply-staining gran- 

 ules which are much like the usually 

 described Nissl bodies for molluscan nerve cells, but it should 

 be noted that these bodies do not have the general concentric dis- 

 tribution so characteristic of Nissl bodies. In close connection 

 with each other and the nuclear membrane, there are various 

 shaped bodies and granules which occupy the remainder of the 

 space around the nucleus. The smaller of these bodies are indis- 

 tinguishable from the cytoplasmic granules, while the two larger 

 are more like nucleoli than anything else. On the side of the nu- 

 cleus opposite to the cone-shaped mass of Nissl granules hereis an 

 interesting condition. Anumber of the cytoplasmic granules have 

 increased slightly in size and form a rather complete boundary to 

 what is evidently a lymph space. In this space there is a solid 

 staining body similar to the two already mentioned. It would 

 seem as if we had an early stage intheformationof the limiting wall. 



Figure 3 reveals one or two addi- 

 tional characteristics. The chromatin 

 shows a tendency to mass around the 

 'periphery of the nucleus sim lar to 

 the condition already described for 

 Haminea. There seems to be an 

 entire absence of Nissl bodies as such. 

 There are two conspicuous lymph 

 spaces sharply limited, apparently 

 Fig. 3. empty. Associated with these two are 



several smaller ones, some likewise empty of stainable substance, 

 others containing one or more bodies. Surrounding these lymph 



