panel.abline(a, b, ...)
panel.abline(coef, ...)
panel.abline(reg, ...)
panel.abline(h= ,v= , ...)
panel.curve(expr, from, to, n = 101,
            curve.type = "l", ...)
panel.rug(x = NULL, y = NULL,
          regular = TRUE, start, end, ...)
panel.fill(col="grey", ...)
panel.grid(h=3, v=3, ...)
panel.lmline(x,y,...) = panel.abline(lm(y~x), ...)
panel.loess(x, y, span = 2/3, degree = 1,
            family = c("symmetric", "gaussian"),
            evaluation = 50, ...)
panel.linejoin(x, y, fun = mean, horizontal = TRUE, ...)
panel.mathdensity(dmath = dnorm, args = list(mean=0, sd=1))panel.abline, numerical vectors giving y and x
    locations respectively of horizontal and vertical lines to be
    added to the plot. For panel.grid, number of horizontal and vertical
    reference lines to be added to the plot; h=-1 anllinesloess.smooth, around which panel.loess is essentially
    a wrapperbwplot for a fuller
    explax, e.g., dnormcol,
      col.line and col.symbol, the last two overriding the first
    for lines and points respectively.panel.abline adds a line of the form y=a+bx or vertical
  and/or horizontal lines. Graphical parameters are obtained from 
  reference.line for panel.grid, and add.line for the
  others (can be set using trellis.par.set )  panel.curve adds a curve, similar to what curve does
  with add = TRUE. Graphical parameters for the line are obtained
  from the add.line setting.
  panel.linejoin treats one of x and y as a factor (according to
  the value of horizontal, calculates fun applied to the
  subsets of the other variable determined by each unique value of the
  factor, and joins them by a line. Can be used in conjunction with
  panel.xyplot and more commonly with panel.superpose to produce
  interaction plots. See xyplot documentation for an example.
  panel.mathdensity plots a (usually theoretical) probability
  density function. Can be useful in conjunction with histogram
  and densityplot to visually estimate goodness of fit.
  panel.axis draws axis tick marks INSIDE a panel. It honours the
  (native) axis scales within the panel, but the locations need to be
  explicitly specified. Used in panel.pairs for
  splom.
  panel.identify is similar to identify. When
  called as part of the panel function, it waits for the user to
  identify points (in the panel being drawn) via mouse clicks.
  Clicks other than left-clicks terminate the procedure. It is less
  sophisticated than identify in the sense that it does not keep
  track of points already identified.
loess.smooth,
  identify, trellis.par.get