ALIMENTARY TRACT OF CULEX PIPIENS 615 



and the chromatin flows out. In the lumen of the newly formed 

 gut appear great numbers of vacuolated 'ghost cells' whose 

 outlines can barely be discerned. And in the midst of these, 

 streams of a gray-blue substance appear, filled with tiny black 

 granules. This is e\ddently the chromatin from the divsintegrat- 

 ing cells. All this material is apparently digested, for it has 

 never been found in the very posterior part of the alimentary 

 tract. 



Such then appears to be the history of the cells of the larval 

 gut tract while that tract undergoes metamorphosis. For a 

 time, metabolism is greatly increased; disintegration follows, with 

 final absorption by the newly-formed imaginal cells. 



Discussion 



These facts with regard to the intestinal cells of Culex may 

 possibly have some bearing upon two of the unsettled cytological 

 questions at present under discussion — the 'Individuality Hy- 

 pothesis' and the 'Kern-plasma Relation.' It might be urged 

 that this is degenerating tissue and that therefore abnormal 

 conditions prevail, but the uniformity and consistency in the 

 behavior of all these intestinal cells lead to the belief that these 

 conditions are normal, that they have a definite place in the life 

 cycle of each intestinal cell of the larva, and that, in question of 

 individuality of chromosomes or 'Kern-plasma Relation,' these 

 cells conform to the laws governing other cells of the body. 



One of the arguments urged against the Individuality Hy- 

 pothesis has been variation in nimiber. But certainly here, 

 variation in number instead of arguing against the theory, seems 

 to give added weight, as has been the case in many of the other 

 exceptions to the rule of constant number. To be sure, we 

 have here a wide variation in the chromosome number, ranging 

 from [six] to a possible seventy-two, but always multiples of 

 three— six, nine, twelve, eighteen, twenty-four, thirty-six, forty- 

 eight. With the exception of one cell, (fig. 27 and the possible 

 exception of fig. 23), no other number was ever found. In some 

 individuals, the 'six series' appears, and in others the 'nine 



