what does variable declaration after function declaration mean?

Question

Looking through glibc sources I run against such a code:

  double
erand48 (xsubi)
     unsigned short int xsubi[3];
{
  double result;

  (void) __erand48_r (xsubi, &__libc_drand48_data, &result);

  return result;
}

Could you explain what does that xsubi declaration between function's header and body mean?

   unsigned short int xsubi[3];

The same thing is with drand48_r:

  int
drand48_r (buffer, result)
     struct drand48_data *buffer;
     double *result;
{
  return __erand48_r (buffer->__x, buffer, result);
}