Scientia Sinica

Fig. Fig.

Fig.

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EXPLANATION OF PLATE I

From a fetus of 34 mm C-R length, estimated at 59 days, showing the beginning of appearance of the ossification centre of the zygomatic bone, Right side view. X 10. :

From a fetus of 42 mm C-R length, estimated at 64 days, showing the appearance of the fronto-sphenoidal process. Left side view. X 10.

From a fetus of 53 mm C-R length, estimated at 7] days, showing the appearance of the orbital process. Right side view. X 10.

Cz., centre of ossification of zygomatic bone; F.p., fronto-sphenoidal process; In., incisive bone; Inf. p., infra-orbital process; Mx., maxilla; O.p., orbital process; Tern., temporal bone; Z.p., zygomatic process. : :