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laminae, thus produced, are added constantly to the lens until it becomes a 

 spherical mass attached to the inner portion of the ciliary body by means of 

 the stalks of the processes. As soon as the lens has become spherical, the 

 outer part of the ciliary body begins to contribute to its growth, for further 

 growth by additions from the inner portion of the ciliary body necessarily 

 produces a lens flattened on the side in contact with the suspensory ligament. 

 Hence, to maintain the spherical form of the lens, a plano-convex segment is 

 produced by the outer portion of the ciliary body. Those cells of the ciliary 

 body which are enclosed between the two segments of the lens degenerate and 

 are absorbed, leaving only the suspensory ligament between the two segments. 

 The constant growth of the lens and of the ciliary body necessitates the exis- 

 tence of three zones in the latter viz. an inner zone of degenerating cells, a 

 middle zone of mature cells, and a marginal zone of immature cells. The lens- 

 forming processes of the immature cells are relatively larger and more conspicuous 

 than those of the mature cells and form a prominent layer between the ciliary 

 body and the adjacent chamber of the eye. The large size and conspicuous 

 position of the processes have led some writers (Paussek '96) to ascribe to them 

 the formation of the entire lens and to assert that the large mature cells of the 

 ciliary body have some unknown physiological function. The mature cells of the 

 ciliary body are oval, cubical or columnar and are attached by their bases to 

 the suspensory ligament. The free end of each cell is drawn out into a long, 

 slender process which is so small compared with the cell and the corresponding 

 portion of the lamina, that it probably serves as a duct which carries the 

 secretion of the cell to the lamina. When isolated these cells are so similar in 

 general appearance to unipolar nerve cells that the writer who has given the 

 best description of them (Hoffmann) believed them to be nerve cells. The cell 

 body is large and stains deeply with nuclear stains. The nucleus is large and 

 the nucleolus conspicuous. While attaining their mature condition , the cells of 

 the inner portion of the ciliary body grow so much that the epithehum formed 

 by them is thrown into radial folds. The inner furrows of these folds are filled 

 by the cell processes while the outer furrows are filled by ridges of the suspen- 

 sory ligament. Thus this outer layer remains a simple palisadal epithelium which , 

 however, in section appears several cells thick. The outer layer of the ciliary 

 body is less folded or remains plane. A pigmented membrane, the continuation 

 of the supporting layer of the retina, lies upon the inner surface of the ciliary 

 body , and , as Hoffman has shown , the cells of the inner part of the ciUary 

 body may be distinguished from those of the outer part by the presence of 

 pigment granules in or between the cells. 



