. The cyclopædia of anatomy and physiology. Anatomy; Physiology; Zoology. 918 TERATOLOGY. and in defective formation of the infe- rior part of the body. Serres hence derived the conclusion, that this malformation is the con- sequence of the want of one of the umbi- lical arteries ; which is however wrong, as the evolution of the whole body may be complete, even when one of the umbilical arteries is wanting. Fig. 599. represents a specimen of this kind. - Fig. a, aorta; b, b, spermatic arteries; c, superior mesen- teric; d, d, common iliacs; e, the single umbilical artery; /, vena cava. M
. The cyclopædia of anatomy and physiology. Anatomy; Physiology; Zoology. 918 TERATOLOGY. and in defective formation of the infe- rior part of the body. Serres hence derived the conclusion, that this malformation is the con- sequence of the want of one of the umbi- lical arteries ; which is however wrong, as the evolution of the whole body may be complete, even when one of the umbilical arteries is wanting. Fig. 599. represents a specimen of this kind. - Fig. a, aorta; b, b, spermatic arteries; c, superior mesen- teric; d, d, common iliacs; e, the single umbilical artery; /, vena cava. Mende even observed in a very well formed child absence of one of the umbilical arteries, together with an unusual course of the umbi- lical vein, which, instead of communicating with the vena portae, opened immediately into the right auricle of the heart. 7. Increased number of the vessels of the cord. — A double umbilical vein is constantly to be found in the Quadrumana of the New World (Rudolphi). In Man the unusual plurality of the umbilical vessels is but ap- parent, as it is produced by the persistence of the vasa oniphalo-mescnterica. 8. Persistence of the umbilical vesicle, is a natural condition in the Onistiti (Rudolphi), and occurs as a deviation in Man. Sometimes it is only its duct that remains united with the small intestine, forming what we call a diverticulum. 9. Constriction of the umbilical cord occurs at the point where the cord penetrates into the abdomen. In the constricted part the vessels, although remarkably narrowed, still allow in some measure the circulation of the blood. The cord is thereby contorted into a spiral. The death of the foetus is its usual effect (Landsberger). Fig. 147. of the second volume of this Cyclopaedia gives a represent- ation of this constriction of the umbilical . cord. 10. The umbilical cord too thick. — Its dia- meter varies from 1*—2£ inches. This is, in general, the consequence of an uncommon accumulation of the Whar
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