HUBRECHT. Pl. M. 
all 
OM 
Fig. 60 and 61. Two surface views of a yet later embryonic shield of the 
shrew. In fig. 60 the annular zone of proliferating entoderm az is indicated 
as well as the ‘primitive streak and the dotted outline mes of the mesoblast wings; 
in fig. 61 the notochord has begun to be formed; a neurenteric pore (72f)/ is 
visible as well as extra embryonic posterior coelom, co. (Vig. 56 to 61 after 
Hubrecht, tl) ee Fig. 62 to 65. Diagrams intended to demonstrate the gradual 
displacement in Tarsius of the embryonic shield from its original position (62) 
towards a position diametrically opposite the placenta (65). The zone a of fig. 16 
is shown in fig. 63 as being at the same time the incipient allantois tube @//: 
in fig. 64 and 65 this becomes a posterior, cylindrical continuation of the enteric 
cavity V7, lengthening as the embryonic shield travels upwards. In 64 and 65 
the placenta P has become a considerable trophoblastic proliferation in cushion 
shape (vide Hubrecht, 99), in Fig. 65 the amnion folds va, “a and the neuren- 
teric canal mc have made their appearance (cf. fig. 99); c extraembryonic coelom, 
HT connective stalk, am amnion (after Hubrecht, ‘07). 
PA 
