[igraph] R2.7.0 fails to show vertex labels on Quartz

[MATSUDA, Noriyuki]

Hello:

  I updated R today to 2.7.0 and encountered with the trouble in  
displaying vertex labels.  The following shows the title but not lables:

>g <- graph.ring(10)
>V(g)$name <- LETTERS[1:vcount(g)]
>plot(g,main="graph.ring")

> warnings()
1: In text.default(x, y, labels = labels, col = label.color,  ... :
  font "Times-Roman" could not be found
 ...........

   I'd appreciate prompt rescue.

MATSUDA, Noriyuki  <Kanji> 松田紀之