From James Hastings Nichols, Corporate Worship in the Reformed Tradition, p. 102-103.

“Lecturing” was a running exposition of Scripture and was especially popular through the system of Puritan [i.e. not Presbyterian] “lectureships,” of endowed preaching posts outside the regular benefices.  The Directory permitted lecturing, but specified that Scripture was to be expounded, it should wait till the end of the chapter.  What was merely permissive soon became general practice.  The minister added an expository “lecture” to his reading of Scripture in addition to the sermon.  The Scots Assembly had to set the hour for morning worship half an hour earlier to accomodate the additional time added by the “lecturing.”

From James Hastings Nichols, Corporate Worship in the Reformed Tradition, p. 109.

…in most cases the legatees of the Westminster Assembly Puritans did not care to maintain the full prescriptions of the Directory.  The anti-liturgical current moved most of them still farther to the left.  Perhaps the most faithful exponents of the Directory after the Restoration were the Episcopalian minority in Scotland, who were distinguished, not by the Anglican prayer book, which they did not follow, but by their use of the Lord’s Prayer, the Creed, and the “Glory be to the Father” in a service modeled on the Westminster Directory.  The Church of Scotland itself had by the end of the century come close to the position maintained by the Congregationalists against the Presbyterians at the Westminster Assembly.  Presbyterians generally gave up the liturgical use of the Lord’s Prayer, despite the recommendations of the Directory, and adopted the Congregationalist fear of the uncommented reading of Scripture.  And eighteenth-century Scottish Presbyteians could get into trouble for following the instructions in the Directory as to reading Scripture and using the Lord’s Prayer.  Even metrical psalmody suffered.  The custom of “lining out,” conceded by the Directory in cases “where many in the congregation cannot read,” became the normal practice in Scotland and America in Presbyterian and Congregational churches.

From James Hastings Nichols, Corporate Worship in the Reformed Tradition, p. 109.

Some measure of the revolution effected by the Puritan movements in Reformed worship can be seen in the contrast with the French experience.  When the storm troopers of the Counter-Reformation drove the Huguenots by the thousands into exile abroad in the 1680’s, many were brought into contace with the churches of England and her American colonies.  Although they were scarcely prepared to accept the Arminianism introduced by the court into Anglicanism in the 1620’s and [that was] virtually official since the Restoration, they found the worship of the English Presbyterians and Congregationalists equally alien.  In worship, the Book of Common Prayer seemed closer to the Calvinist heritage than did anti-liturgical Puritanism.

From James Hastings Nichols, Corporate Worship in the Reformed Tradition, pp. 58, 59.

The Huguenots quite caught Calvin’s concept of congregational psalmody.  It became their hallmark, in homes, in corporate worship, or on the battlefield.  The French Discipline required all to own and bring their liturgical psalters, and to share in the singing.  The synods took the sung prayers very seriously.  Figeac censured the practice of lining out (1579).  Rochelle censured those who did not sing in service (1581).  Synods o fthe early seventeenth century required the use of the whole psalm and ruled against the use of one or two stanzas only.  They were not strictly held to the psalms.  Beza had introduced some hymns and these were authorized by the synod of Montpellier (1598).  However, in general, little but psalms were sung in the sixteenth- and seventeenth-century French Reformed Church.