On page 203 of M. M. Azami's "Studies in Early Hadith Literature" (in
my copy of the third edition) in the fifth chapter entitled "The Book"
I read: "To separate one hadith from the other, they made a small
circle instead of a full stop. This kind of inscription is found at
the beginning of the second centruy, e.g., the book of Abu al-Zinad
from al-A'raj." with a footnote that references Ramhurmazi, al-Khatib
al-Baghdadi and al-Sam'ani.
Azami makes nothing of this although he expresses an interest in
Malik's sources.
I conclude that by Ramhurmazi's time (around 350 AH) someone had done
for the al-A'raj collection exactly what was done for the Hammam ibn
Munabbih collection that Muhammad Hamidullah has publicized. That is,
I assume that, rather than 'Abd al-Razzaq incorporating an earlier
book into the Musannaf, someone extracted the book, called the Sahifah
from the Musannaf. In the same way it appears that someone once did
the same thing by extracting the Al-A'raj collection from the Muwatta.
People, of course, became confused and assumed that what they had was
a book Abu al-Zinad actually possessed.
The two collections of sayings are not identical but there is a great
deal of overlap and the wording of hadiths that occur in both
collections are almost identical. I believe there is no escaping that
they have a common source.
Both the Musannaf and the Muwatta are very early sources and the
common source of both collections must lie very near the birth of
Islam. I do not see how we can separate it from Abu Hurayra himself.
Otherwise how can we explain the two paths of descent?
I have suggested that Abu Hurayra (the one who is mentioned so often)
is not a real person at all, but rather a document. One of the two cat
hadiths occurs in the Hammam collection. I imagine the document to
have originally been anonymous and untitled and to have gained its
name the same way the surats of the Qur'an were named - from a
striking part of the contents.
There may well have been a Dawsi gentleman, perhaps Said bn al-
Musayyib's father-in-law, whom later generations imagined wrote the
document. He might have.