231 



and stained material, there are to be noticed very great changes 

 from the conditions found in the cells of the well fed animals. The 

 whole cytoplasm of the cells has the appearance of a coarse foam 

 structure. Here and there may be found the remnants of previously 

 existing solid particles of stored up material. With the lack of food 

 and the consequent demand upon the storage supplies there has been 

 a disappearance of the energy-producing substances stored within the 

 nerve cells during the time of plenty. 



Limas maximus. 



Our previous reports concerning the pigmented granules found in 

 the ganglion cells of Limax maximus are now subject to certain modi- 

 fications on account of the fact that the length of time during which 

 the animals were under obser- 

 vation was not so long as it should 

 have been. 



We are now in position to make 

 a more complete report upon this 

 species. In March 1909 the junior 

 author secured from California a 

 large number of specimens of the 

 mollusc in question. As in our 

 previous studies, a part were killed 

 at once and their nerve cells 

 examined, some in the fresh un- 

 stained condition, others after being 

 sectioned and stained. As in the 

 examinations previously made, it was 

 found that the nerve cells were well 

 supplied with pigmented granules 

 and with the more transparent 

 vacuoles. The length of the journey 

 (more than three thousand miles) 

 made by these slugs, their con- 



Fig. 3. Limax maximus. Photo- 

 graph of nerve cells under the ^/j, inch 

 homog. immersion objective. The animal 

 was transported 3500 miles and was 

 without food six months. Small granules 

 and vacuoles are scattered through the 

 cytoplasm. With longer starvation other 

 specimens showed a decrease, or even 

 entire disappearance, of granules and a 

 corresponding increase in the number of 

 clear vacuoles. 



stant jarring, lack of food, etc., 



had all acted as more or less constant sources of stimulation, and 

 had resulted in using up some of the stored material with which the 

 cells had been supplied. 



The animals upon which the further observations were made 

 were kept in an iron tank, the bottom of which was moist. They re- 

 mained very quiet; only rarely were they observed to move about 



