MURI'HV: REPORT OX THE SOUTH CHORGIA EXPEDITION. 9" 
The o:losso-hyal has a lonolh of 0.35. and is Infid posteriorly, 
while its entire length rests u])on an elevation of the floor of 
the motith whieh rises up in front of it. a])|)arently for thai 
ptn-pose. It is co\-ered 1)_\- the common l)nceal mncous mem- 
hrane. 
A\'hen the delicate skin of the head has heen entirel}' re- 
moved, it will he ohserxed that the eves are verv lart^x' and 
hulo-jng-. Superiorly, in the frontal re.L^ion, the}' are separated 
from each other hv an interwal of 0.35 mm., and either one 
has a mean diameier of o. u mm. h'.ilher aural al^crtiirc is 
exceedingly minute, and after emjiloying ever;, means <at my 
command to find its external o])ening. I failed to disco\er an_\-; 
the nicafiis. at this stage of dexelopment in riialacrncorax a. 
gcorgiaiuis at least, terminates as a blind tube on the inner 
surface of the skin. 
All the hones of the skull .are now either in elementar\- 
cartilage or in menihr.ane. ,accor(ling to their mode of develop- 
ment. .\s menihr.ane hones, the pai-ictals are thin and tr.ans- 
parent. and the large hr;rin-mass can easily he discerned 
through them. .\nleriorl\'. this part of the cranium mounds 
U]) above the frontal region .and eyed)alls. to be less prominent 
lateralh- and ])osteriorly. A gener.al. though not \ery deep, 
cavitv marks the frontal region, which terminates ;it tlie 
cranio-facial .are.a at the base of the superior mandilile. 
After the cei)halic integument has l)een renio\-ed, the thin 
parietal bones { f>a ) shrivel and collai)se (as shown in I'ig. J). 
crowding and distorting the brain-mass ;is the\' do so. The 
superior cervical muscles ( ;/ ) are very strong e\ en at this early 
stage of de\'elopment. and immediatelv anterior to them, on 
either side, is seen the jugular vciu. which here, as usual in 
birds, is ;i single tnmk. ! )n the right side this xein is larger 
than that of the left. 
As shown in l-'ig. _'. several lateral branches join the jugular 
on the side of t!ie neck; these come from the skin, the muscles 
.and the lesoph.agus. 
Between the base of the cranium and the os furcula. the 
neck forms a double cur\-e like the letter S. the convexit\- 01 
the superior moiety being ])osteriorly-directed, while the lowc 
half ])resents the re\-ersed curxature superiorly; the trachea 
