Fig. 12 Developing rod and cone visual cells, from the retina of a 345-mm. 
(six months) human fetus. /, diplosome in a Miiller’s fiber at the level of the 
external limiting membrane; C, diplosome in a cone cell; F, fiber growing out from 
the cone diplosome; FR, diplosome in a rod visual cell. XX 1000. (AfterSeefelder. 
From Jordan and Ferguson’s Text-book of Histology.) 
Fig. 13 Two early stages in the development of the rod and cone visual cells 
in the chick. A, from twelve-day embryo, showing the visual cell-buds con- 
taining mitochondria. L.e., external limiting membrane; C. v., visual cell; 
R.e., external reticular layer; C.p., bipolar cells. B, from one-day-old chick, 
showing two complete rods and one cone, both elements containing a large lipoid 
spherule (@) and mitochondria. The cone contains an ellipsoid (1); seg. int., 
internal segment; seg. ext., external segment. X 2000. (After Leplat. From 
Jordan and Ferguson’s Text-book of Histology.) 
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