. A manual of zoology. Zoology. 4o6 CIIORDATA axial skeleton and arise from tlie ossifications in the skin (scales) or in the mouth (teeth), alreaih" referred to (p. 451). They sink into the deeper portions and apply ihemsehes to the axial skeleton, especially to those parts where, from lack of cartilage, no primary bones can be formed. It is not settled how far these distinctions are \'alid. According to Gegen- baur all ossification arose jirimarily in the skin or mucous membranes, and primary bones are merely memlirane bones which have entered the. 515.—Chondrocranium of A }>ip
. A manual of zoology. Zoology. 4o6 CIIORDATA axial skeleton and arise from tlie ossifications in the skin (scales) or in the mouth (teeth), alreaih" referred to (p. 451). They sink into the deeper portions and apply ihemsehes to the axial skeleton, especially to those parts where, from lack of cartilage, no primary bones can be formed. It is not settled how far these distinctions are \'alid. According to Gegen- baur all ossification arose jirimarily in the skin or mucous membranes, and primary bones are merely memlirane bones which have entered the. 515.—Chondrocranium of A }>iplihiijia. mip, aiiUivliilal process; i7/>, asccnrlina; process of C|uadrate; c, cornu trabccula-; c, clhmoiil plate; , stapedial process; (, trabecula; Ire, crest of trabecula; V, VII, VIII, foramina for V, VII, VIII nerves. cartilages and replaced them. Accordingly it is conceivable tliat the same bone in one animal may arise as a membrane bone and in another as a primary lione, a point of importance in deciding the homologies and nomeirclature of many bones. It is but just to say that tills view is not universally acceptetl. The diondrocraniiim is most complete beside and lieneath the brain (fig. 515). This basal portion is a direct continuation of the vertebral column, and a part of it (the parachordals) embraces the anterior end of the notochord, while parts (the irabcciihc) extend in front of the. 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 Hertwig, Richard, 1850-1937; Kingsley, J. S. (John Sterling), 1854-1929, ed. and tr. New York, H. Holt
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Keywords: ., bookcentury1900, bookdecade1910, booksubjectzoology, bookyear1912
