GERM CELLS IN THE ARTHROPODA 117 
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Fia. 37.—Calligrapha. A. A germ cell of C. multipunctata shortly after 
being cut off from the egg. 8B. Division of a primordial germ cell. 
C. Longitudinal section through egg of C. bigsbyana at blastoderm 
stage; the posterior end was killed with a hot needle just after 
deposition. D. Longitudinal section through uninjured egg at 
same stage. E. Two ectoderm cells (e), two mesoderm cells (m), 
and two germ cells (g.c.) from an egg three days old. F. Germ 
cell during migration into the embryo (three days old). G.H.I. Longi- 
tudinal sections through eggs centrifuged for one hour, two hours, 
and four hours respectively. bl = blastoderm; g.c.d. = granules of 
pole-dise ; k = killed portion of egg; Ahbl. = keimhautblastem; p. 
posterior; pgc=primordial germ cells; » = vitellophags; 2.2. 
vesicular zone; y. = yolk. 
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