Cloacal morphology in its relation to genito-urinary and rectal diseases(With 54 plates and 93 illustrations.) . Fis. 3.—Ventral surface of tail. {Johns Hopkins Bulletin.). Fig. 6.—Showing contracted tail. {Johns Hopkins Bullelin.) in the ancestral stock from which the human species has descended. They form a true external tail. _ , , . , ^ ,. The coccyx is not a stable group of bones but is on the way to disappearance. This is vividly shown by the reduction of the typical external tail of the humanembryo so that by the time adult Ufe is reached there is ordinarily no trace of the ex-ternal ta
Cloacal morphology in its relation to genito-urinary and rectal diseases(With 54 plates and 93 illustrations.) . Fis. 3.—Ventral surface of tail. {Johns Hopkins Bulletin.). Fig. 6.—Showing contracted tail. {Johns Hopkins Bullelin.) in the ancestral stock from which the human species has descended. They form a true external tail. _ , , . , ^ ,. The coccyx is not a stable group of bones but is on the way to disappearance. This is vividly shown by the reduction of the typical external tail of the humanembryo so that by the time adult Ufe is reached there is ordinarily no trace of the ex-ternal tail and the internal tail is a mere rudiment attached to the tip of the sacrum. Now and then the external tail is not reduced and we have a genuine tailed man. Pasre Twelve From an examination of the coccygeal bones in the adult we might suppose that theyrepresented the bodies only of the caudal vertebrae but embryology shows us that isnot the case. During development they possess membranous, and in the case of the first andsecond coccygeal vertebrae, cartilaginous neural processes. The articular and transverse processes are incomplete or entirely lacking. Although
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