. Journal of anatomy . es was estimated by measuring thelength of the basilar plate (from the basion to the posterior point of theattachment of the vomer to the sphenoid) in individuals at various stagesof development. During the eruption of the milk teeth the basilar platein the young of the giant anthropoids measures about 25 nun. The youngof man and of the gorilla are distinguished by the shortness of the basi-occipital part. The greatest elongation of the basilar plate takes place in Description of a New Craniometer, etc. 267 the gorilla. With the elongation of the basilar plate the condyl
. Journal of anatomy . es was estimated by measuring thelength of the basilar plate (from the basion to the posterior point of theattachment of the vomer to the sphenoid) in individuals at various stagesof development. During the eruption of the milk teeth the basilar platein the young of the giant anthropoids measures about 25 nun. The youngof man and of the gorilla are distinguished by the shortness of the basi-occipital part. The greatest elongation of the basilar plate takes place in Description of a New Craniometer, etc. 267 the gorilla. With the elongation of the basilar plate the condyles arethrust backwards, as shown in fig. 9 ; or, to be more accurate, the facialpart of the skull is thrust forwards and upwards, the articulation of thecondyles with the atlas preventing any real backward migration as regardstheir position relative to the trunk. The growth of the basilar plate throwsthe snout away from the cervical part of the spinal column so as toaccommodate the great mandible masticatory o(uJlJt Fig. 9.—Diagrammatic representation of the changes in the basilar part of the skull ofthe gorilla from the end of the eruption of the milk teeth until adult age. The blackoutline represents a tracing of the young skull ; the shaded and stippled areas, thegrowth changes. 100 = the length of the basilar plate at the end of the milkdentition ; occ. con. , the position of the occipital condyles in the youngest stage ;occ. con. adult, position in the adult; for. mag., the foramen magnum. Using the length of the basilar plate during the eruption of the milkteeth as a standard of 100, its increase in the male gorilla may be statedas 120 per cent., in the male orang 80 per cent., in the chimpanzee 70 percent., in man 20 per cent. The Siamang and gibbon agree with the gorillaand pronograde apes, and show an increase of 110 per cent. In anthropoidapes this is a real growth, for their cranial capacit}^ has reached its fullsize at the end of the eruption of th
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Keywords: ., bookcentury1800, bookdecade1860, booksubjectanatomy, bookyear1867
