[XeTeX] Ancient Greek in Polyglossia

[Juan Acevedo]

Hello,

The following minimal file, running in a Mac (xdv2pdf), under XeTeX  
0.999.2:
---------------
%!TEX TS-program = xelatex
%!TEX encoding = UTF-8 Unicode

\documentclass[12pt,letterpaper,openany]{book}

\usepackage{fontspec,xltxtra,xunicode}

\usepackage{polyglossia}
	\setdefaultlanguage{spanish}
	\setotherlanguage{ancientgreek}
	
\begin{document}

\begin{ancientgreek}
«᾽Εγώ σου λογιώτερος, ἐγώ σου ἄρα  
κρείσσων».
\end{ancientgreek}

\end{document}

-----------------------------------

is giving me the message:

! LaTeX Error: Environment ancientgreek undefined.

What should I do here? From Polyglossia documentation, I expected  
ancientgreek.ldf to be there. I have searched for it unsuccessfully.

Are the newly CTAN uploaded utf-8 hyphenation patterns related to  
this? If so, how to use them?

Thanks for any help

Juan