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XIII. Remarks on the voluntary Expansion of the Skin of the 
Neck , in the Cobra de Capello or hooded Snake of the East 
Indies. By Patrick Russell, M. D. F. R. S. With a Description 
of the Structure of the Parts which perform that Office. By 
Everard Home, Esq. F. R. S. 
Read June 14, 1804. 
The remarkable expansion of the skin of the neck, in the 
Coluber Naja of Linn^us, or Cobra de Capello of the East 
Indies, and which constitutes a principal character of the species, 
is produced by an apparatus hitherto, as I believe, very imper- 
fectly described. It is a voluntary action, totally distinct from 
that inflation which all serpents, when irritated, are more or less 
capable of, and which the Coluber Naja also assumes, at the 
same time that it expands its hood. 
In botanical excursions in India, fragments of serpentine 
skeletons, made by the black ants, were occasionally met with ; 
but, in such as were supposed to belong to the Coluber Naja, the 
peculiar disposition and structure of the cervical ribs, so different 
from that in other serpents, had escaped me. 
In other serpents, the ribs, from the first vertebra to those 
of the middle of the trunk, gradually increase in length ; thence 
they gradually shorten or decline, to near the end of the tail, 
where they disappear, or are transformed into short eminences ; 
but, in the Coluber Naja, the cervical ribs gradually lengthen to 
the tenth or eleventh, after which, they successively shorten to 
the twentieth. The ribs, again increasing in length, are, at the 
