TROPHOSPONGIUM OF THE NERVE CELL 527 
to be well developed. Specimens exhausted in a water wheel 
did not show any stronger development, nor did one that was 
more or less under the influence of chloretone for two days. The 
sections illustrated in figures 1 to 9 were made from a cell of an 
animal apparently perfectly normal. Because of the presence 
of the structure in the crayfish nerve cells in normal and in 
abnormal conditions it is evident that in all probability the 
trophospongium is a permanent structure, not a transitory. 
No very positive opinion concerning the function of the 
trophospongium has been expressed. The presence of blood 
capillaries as observed by Holmgren in Lophius logically indicates 
the possibility of a nutritive function. Theoretically a nutritive 
function is possible even in the absence of blood capillaries, as 
the trophospongium increases the capsular surface in contact 
with the cytoplasm thereby increasing the area of the osmotic 
surface. The absence of capillaries in the crayfish does not of 
necessity preclude the possibility of such a function. Several 
authors suggest that this is the function of the trophospongium. 
Logically there is a correlation between the morphology and the 
physiology of an organ. The crayfish nerve cell shows the de- 
velopment of the trophospongium into a structure admirably 
fitted for mechanical support. The anastomosing walls and 
capsules divide the cytoplasm into many lobes and offer sub- 
stantial support to them. The smaller cells with an area pro- 
portionally greater in contact with the cell capsule do not have 
the trophospongium as strongly developed. The idea of a sup- 
porting function has been expressed by some authors, as Legendre 
and Gariaeff. It is not unreasonable to suppose that the struc- 
ture functionates primarily as a mechanical support and seconda- 
rily as a nutritive organ. 
