. Bulletin of the Museum of Comparative Zoology at Harvard College. Zoology. Figure 3. Diagrammatic sketch of the head of a) fresh-water plover, the killdeer, (Charadrius vociferus) and b) salt-water plover, ringed plover, {Churadrius hiaticula) to show the difference in the size of the nasal glands (G) and their relationship to the eyes (E). One problem remains. What is the basis of the correlation between the size of the nasal glands and the degree of ossification of the supraorbital rims? Support for the glands is easily pro- vided for by the heavy membranes present in this region in those
. Bulletin of the Museum of Comparative Zoology at Harvard College. Zoology. Figure 3. Diagrammatic sketch of the head of a) fresh-water plover, the killdeer, (Charadrius vociferus) and b) salt-water plover, ringed plover, {Churadrius hiaticula) to show the difference in the size of the nasal glands (G) and their relationship to the eyes (E). One problem remains. What is the basis of the correlation between the size of the nasal glands and the degree of ossification of the supraorbital rims? Support for the glands is easily pro- vided for by the heavy membranes present in this region in those species with poorly ossified rims — a support of bone is not needed. A number of experiments that have a direct bearing on this problem have been reported by Murray (1936) in his general treatise on bone. In the treatment of the functional changes in bone, he discusses (p. 78) the yet unexplained fact that "other pressures can cause either atrophy or at any rate limitation of growth of bone in the direction of the ; Blood vessels, tendons and muscles can press against the surface of a bone and restrict growth of the bone at that point. Several experi- ments were cited in which the bone grew after the overlying muscle had been removed. A large nasal gland would exert a similar pressure on the bone of the supraorbital rim and in this way prevent development of bone in this region. This could be experimentally verified by a unilateral removal of the gland and examination of the skull for changes after an appropriate period. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Harvard University. Museum of Comparative Zoology. Cambridge, Mass. : The Museum
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