Mass. Gen. Laws ch. 185 § 48
Immediately upon the entry of the judgement of registration, the recorder shall send a certified copy thereof, under the seal of the court, to the register of deeds for the district or districts where the land lies, and the register, as assistant recorder, shall transcribe the judgement in a book to be called the registration book, in which a leaf or leaves in consecutive order shall be devoted exclusively to each title, and note therein the day, hour and minute when said judgement is transcribed. The entry made by the assistant recorder in this book in each case shall be the original certificate of title, shall be signed by him and sealed with the seal of the court. All certificates of title shall be numbered consecutively, beginning with number one. A certified copy of the judgement of registration shall be filed and numbered by the assistant recorder, with a reference noted on it to the place of record of the original certificate of title. If, however, a complaint includes land lying in more than one district, the court shall cause the part lying in each district to be described separately by metes and bounds in the judgement or judgements of registration, the recorder shall send to the assistant recorder for each registry district a copy of the judgement containing a description of the land within that district, and the assistant recorder shall register the same; and thereafter, for all matters pertaining to registration, the portion in each district shall be treated as a separate parcel of land.
Mass. Gen. Laws ch. 185, § 48