We make three points. First, even if Finlay et al.'s proposeddevelopmental mechanisms hold, there remains great scope forselection on specific brain structures. Second, the positivecovariance among the size of brain structures provides far lesssupport for the proposed developmental mechanisms than Finlay et al.acknowledge. Third, even if the proposed mechanisms are the primarysize determinants for most brain structures, these structures shouldnot be considered “spandrels.”