Embryos and Nestlings of Centropus sinensis. 655 
Stage 3 (figs. 4& 5, p. 661). I have also seen a very young 
embryo of this species, in which prominent feather-papillae 
occurred in three definite regions :—A double tract from each 
side of the head immediately above the eye to the pygidium, 
and in the areas subsequently occupied by the pt. liumeralis 
and pt. femoralis respectively. The foot of this embryo had 
not yet become zygodactylous. 
Figs. 1, 2. 
Nestling of Centropus sinensis, Stage 2. 
Fig. L—Dorsal aspect, showing the form of the pterylae and apteria. 
Compare the form of the pteryla spinalis with that of Stage 3, 
fig. 4. 
Fig. 2.—Ventral aspect, to show the incomplete pteryla ventralis in the 
embryonic stage. 
Explanation of the lettering, 
apt, coll. lat. = apterion colli laterale. 
apt.sp. — „ spinale. 
pt. cap. = pteryla capitis. 
pt. coll. lat. — „ colli lateralis. 
pt. hum. = „ humeralis. 
pt. sp. = „ spinalis. 
pt. cr. == „ cruralis. 
pt.f. = „ femoralis. 
pt.v. = „ ventralis. 
= apterion between pt. femoralis and pteryla 
spinalis. See p. 657. 
Stage 1. —The trichoptiles are now at the highest point of 
their development. The longest, those on the head and back, 
measure 30 mm., or about one-third of the total length of 
2 y2 
