4. The medium Sections. The סדרים/Sedarim, and their use. The Medium Sections the Hebrews call סדרים/Sedarim, Orders, or sections briefer than the Parashot, inserted by the Masoretes[1] into the Sacred Books, so that according to the coherence or diversity of matters those texts might be separated through all the Books of the Old Testament by which they are shared. Thus, for example, while Genesis has twelve Parashot, the same has forty-three Sedarim.
[1] The Masoretes were mediæval Jewish scribes (laboring from the fifth to the tenth centuries AD), responsible for the preservation and propagation of the traditional text of the Hebrew Scriptures.
De Moor's Didactico-Elenctic Theology (http://www.lulu.com/shop/steven-dilday/de-moors-didactico-elenctic-theology-chapter-ii-concerning-the-principium-of-theology-or-holy-scripture/hardcover/product-23800269.html): 'Furthermore, our AUTHOR mentions the Jews’ סְדָרִים/ Sedarim/Orders: by which word, סֶדֶר, or סדרא in Chaldean, the greater Parashah is frequently signified in the final Masorah, which also obtains in the writings of other Rabbis. Yet, sometimes from the distribution of the Masoretes a Seder constitutes a subdivision of the Parashot, whence it happens that Genesis has twelve Parashot, but forty-three Sedarim, and so on. And into Sedarim of this sort other books also, which do not admit Parashot, are found to have been divided by the Masoretes; so that Joshua has fourteen Sedarim, Jeremiah has thirty-one, etc. Now, this later division of the text is of no use today, and is altogether obsolete.'