The development of the human body; a manual of human embryology . Fig. 49.—A, Embryo S2, 15 mm. Long (showing Ectopia of the Heart) ;B, Embryo L3:, mm. Long.—{His.) In the embryos xxxv (S2) and xcix (L3) (Fig. 49, A andB) of His collection the straightening out of the neck bendis proceeding, and indeed is almost completed in embryoxcix, which begins to resemble closely the fully formedfetus. The tail filament, somewhat reduced in size, stillpersists and the rotundity of the abdomen continues to bewell marked. The neck region is beginning to be distin- IOO THE DEVELOPMENT OF THE HUMAN BODY
The development of the human body; a manual of human embryology . Fig. 49.—A, Embryo S2, 15 mm. Long (showing Ectopia of the Heart) ;B, Embryo L3:, mm. Long.—{His.) In the embryos xxxv (S2) and xcix (L3) (Fig. 49, A andB) of His collection the straightening out of the neck bendis proceeding, and indeed is almost completed in embryoxcix, which begins to resemble closely the fully formedfetus. The tail filament, somewhat reduced in size, stillpersists and the rotundity of the abdomen continues to bewell marked. The neck region is beginning to be distin- IOO THE DEVELOPMENT OF THE HUMAN BODY. guishable in embryo xxxv and in embryo xcix the eyelidshave appeared as slight folds surrounding the conjuncti-val area. The nose and forehead are clearly defined bythe greater development of the nasal groove and the nosehas also become raised above the general surface of the. Fig. 50.—Embryo Wt, 23 mm. Long.—(His.) face, while the external ear has almost acquired its finalfetal form. These embryos measure respectively about15 and mm. in length.* * The embryo xxxv presents a slight abnormality in the great pro-jection of the heart, but otherwise it appears to be normal. THE EXTERNAL FORM OF THE BODY. IOI Finally, an embryo—again one of those described byHis, namely, his lxxvii (Wt) having a length of 23 mm.—may be figured (Fig. 50) as representing the practicalacquisition of the fetal form. This embryo dates fromabout the end of the second month of pregnancy, andfrom this period onward it is proper to use the term fetusrather than that of embryo. The changes which havebeen described in preceding stages are now complete andit remains only to be mentioned that the caudal filament,which is still prominent, gradually disappears in laterstages, becoming, as it were, submerged and concealedbeneath adjacent parts by the development of the but-tocks. T
Size: 1186px × 2106px
Photo credit: © The Reading Room / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1900, bookdecade1900, booksubjectembryol, bookyear1902
