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THE AMERICAN NATURALIST [Vol. XLV 



cells of several animals belonging to widely separated 

 groups are supplied with extra nutritive material. This 

 is true in the Diptera, Chironomus (Weismann, '63) and 

 Simula (Metschnikoff, '66), in the Lepidopteron, Endro- 

 mis (Schwangart, '05), in the Elasmobranchs (Beard, 

 '02), in the Teleosts (Eigenman, '92), in the Amphibia 

 (Nussbaum, '80), and in the Eeptilia (Allen, '06). 



It has already been pointed out (Hegner, '09) that the 

 pole disc granules may be nutritive material. ' ' That the 

 pole-cells need special means of nourishment is doubtless 

 the case, for contrary to the condition in the blastoderm 

 cells, they are at an early period entirely separated from 

 the yolk, and later use up energy in their migration" (p. 

 275). If this is true, and as Wieman ('10) claims, the 

 pole disc granules are derived from the yolk stream, our 

 germ cell determinant hypothesis is not weakened, but 

 gains a distinct argument in its favor. 



It is interesting to note in this connection that two of 

 the foremost investigators of the relation of the acces- 

 sory chromosomes to sex determination are inclined to 

 believe in the quantitative hypothesis, i. e., that the egg 

 which is fertilized by the spermatozoon containing the 

 accessory develops into a female because there is more 

 chromatin present, and that this plus amount influences 

 the metabolism of the cell and its descendants (Wilson, 

 '10; Morgan, '10). This hypothesis suggests the theory 

 of sex advocated by Geddes and Thomson ('89), that 

 "the female is the outcome and expression of prepon- 

 derant anabolism, and in contrast the male of prepon- 

 derant katabolism" (p. 132). In Sagitta (Elpatiewsky, 

 '09), however, it is the male primordial germ cell and not 

 the female that acquires the larger part of the "beson- 

 dere korper." 



Although neither of the two possibilities advanced in 

 the foregoing pages may be correct, nevertheless it seems 

 certain that the peculiar bodies in the primordial germ 

 cells of the animals described above should be named 

 "germ cell determinants." In any event, the attention 

 of investigators ought to be directed toward the problem 

 of discovering the origin and complete history of these 



