The numbers across the top are these same subtests. So, for example, if the variable for IQ across one side and the variable for a language arts test score on the other side intersect at .50, then that is the correlation between IQ on the HSPT and the language arts test score. Some authors place a 1.00 in the matrix where a variable is correlated with itself. Others leave this point blank or place a dash wherever this occurs. Some authors print only the upper one-half of a correlation matrix, since the lower half is the mirror image and thus, redundant.
Notation is r, with pb subscript.
Biserial is used when one variable is continuous and another is usually continuous, but which is forced into a dichotomy. This dichotomy is artificial. Notation is r with b subscript. Phi is when each of the varibles are naturally occuring, dichtomies. Ex. - gender with handedness.