THE FIFTH WEEK. 



501 



The hind-limb is slightly behind the fore-limb in its develop- 

 ment, and at the end of the fifth week the toes are only just 

 commencing to appear. 



The fore- and hind-limbs of each side are still connected by 

 a low and inconspicuous Wolffian ridge. During the fifth week 

 the tail (Fig- 205) is more conspicuous than at any other stage 



FIG. 210. A Pregnant Uterus of .about the fortieth day. The uterus has been 

 opened from the ventral surface, and the decidua reflexa and chorion cut 

 through by a crucial incision, and the flaps turned aside to expose the 

 embryo. The embryo is still inclosed in the amnion, and the small yolk- 

 sac, with its long stalk, are seen lying between the amnion and the 

 chorion. At the upper part of the figure the apertures of the Fallopian 

 tubes are seen. (From Kolliker, after Coste.) x f. 



in development ; it is a thin pointed projection, usually bent 

 either laterally, or backwards, by the pressure of adjacent parts. 



6. The Sixth Week. 



During the sixth week the embryo increases in size, though 

 not so rapidly as in the earlier stages. At the commencement 

 of the week it is about 15 mm. long, and at the close about 19 

 or 20 mm., but the actual measurements depend rather on the 



