52 DR D. WATERSTON AND DR A. CAMPBELL GEDDES ON EMBKYO PENGUINS 



It ended in a somewhat spatula-shaped extremity. The hind limb formed a spatula- 

 shaped protrusion. 



Duck Embryo, 12 Days. (Figs. 16 and 20.) 



The embryo was fully developed, the integument was strongly marked, and there 

 were down papillae on two short lines at either side of the tail. The eye prominences 

 were very marked ; the head and beak were soft and pliable except at the point of the 

 beak, where there was a small white nodule of keratin. The fore limb showed distinct 

 division into upper arm, forearm and hand. The pollex was prominent. 



2. Gcntoo Penguin Embryo, 13 Days. (Fig. 11.) 



The embryo was not fully formed. The head was soft and the brain showed 

 through it. The beak was short, the eyes were prominent, the fore limbs were short, 

 but showed plainly the elbow joint, and had a flattened, spade-like tip : to the 

 naked eye there was no sign of digitation. The hind limbs were short, the ankle was 

 unformed, the end was spatular and showed signs of three digits, the tail was relatively 

 long and was much curved ventrally. 



Duck Embryo, 13 Days. (Fig. 18.) 



The embryo was fully formed. Down was appearing in lines on the back and sides 

 of the embryo, and laterally on the neck ; otherwise as for 12 days. 



3. Gentoo Penguin Embryo, 1 4 Days. 



The embryo was not fully formed, the head was soft, the brain showing through it. 

 The beak was short, the eyes prominent ; the fore limbs short, but well formed ; the 

 hind limbs were short, spatular protrusions. The heart showed distinctly, shining 

 through the thin anterior wall of the thorax. The tail was relatively long and much 

 curved ventrally. 



Duck Embryo, 14 Days. (Fig. 21.) 



Down papillae were seen all over the embryo, especially along the dorsal tracts and 

 on the tail. The eyes were widely open. 



4. Gentoo Penguin Embryo, 15 Days. (Fig. 13.) 



The embryo was small, the beak was beginning to grow forward. The fore limbs 

 were small and soft, but fully formed. The hind limb showed no division into the 

 toes, but ended in flat, spatular extremities. There was no sign of the fourth toe 

 independent of the flattened extremity. The tail was relatively long and curved 

 ventrally. 



Duck Embryo, 15 Days. (Fig. 22.) 



Down was appearing upon the head along a well-defined tract which looped round 

 the eye from behind. 



(ROT. soc, EDIN. TRANS., VOL. XLVII., 238.) 



