. Biology of the vertebrates : a comparative study of man and his animal allies. Vertebrates; Vertebrates -- Anatomy; Anatomy, Comparative. 2^0 Biology of the Vertebrates than the harder outer edge of the unguis, thus insuring a constantly well- shod foot with a sharp hard edge, in spite of destructive contact with rocky ground. (c) Nails. Nails occur in man and other primates where they reinforce and protect the sensitive finger pads which play such an incalculable role in life. A person who attempts to pick up a pin, for example, with the fingers encased in gloves quickly realizes how much t
. Biology of the vertebrates : a comparative study of man and his animal allies. Vertebrates; Vertebrates -- Anatomy; Anatomy, Comparative. 2^0 Biology of the Vertebrates than the harder outer edge of the unguis, thus insuring a constantly well- shod foot with a sharp hard edge, in spite of destructive contact with rocky ground. (c) Nails. Nails occur in man and other primates where they reinforce and protect the sensitive finger pads which play such an incalculable role in life. A person who attempts to pick up a pin, for example, with the fingers encased in gloves quickly realizes how much these struc- tures can aid. The human nail, which corresponds to the unguinal part of the claw flattened out, is made up from closely compacted epidermal cells of the stratum lucidum, that is, the lifeless remains of what were once Malpighian cells. During its growth the distal part of the nail is continually advanced toward the tip of the finger or toe by addi- tions from a thickened germinal matrix of Malpighian cells at its base, the position of which, particularly on the thumb, is marked by a white half moon, or lunula (Fig. 184). The pinkish color of the nail, aside from the lunula, is due to its trans- lucency which allows the blood beneath to show through. The lunula is white because the mass of Malpighian cells forming the nail-bed is so thick that the blood does not show through. Upon pressure the blood in the. Fig. 184. Tip of finger, n, nail; l, lunula; c, cor- neum (epony- chium) encroach- ing upon the nail at its base. Corneal Layer--fgg~ Eponychium Terminal Phalanx--7—: (Bone). 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 Walter, Herbert Eugene, b. 1867; Sayles, Leonard Perkins, 1902-. New York : Macmillan Co.
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Keywords: ., bookcentury1900, booksubjectanatomycomparative, booksubjectverte
