Eusebius quotes from Agrippa Castor, a contemporary and opponent from the orthodox side, a statement that 'he wrote four and twenty books (presumably of commentary) upon the Gospel' [Endnote 189:1].
Clement of Alexandria gives rather copious extracts from the twenty-third of these books, to which he gave the name of 'Exegetics' [Endnote 189:2].
Tischendorf assumes, in a manner that is not quite so 'arbitrary and erroneous' [Endnote 189:3] as his critic seems to suppose, that this Commentary was upon our four Gospels.

It is not altogether clear how far Eusebius is using the words of Agrippa Castor and how far his own.

If the latter, there can be no doubt that he understood the statement of Agrippa Castor as Tischendorf understands his, i.e.as referring to our present Gospels; but supposing his words to be those of the earlier writer, it is possible that, coming from the orthodox side, they may have been used in the sense which Tischendorf attributes to them.

There can be no question that Irenaeus used [Greek: to euangelion] for the canonical Gospels collectively, and Justin Martyr may _perhaps_ have done so.
Tischendorf himself does not maintain that it refers to our Gospels _exclusively_.

Practically the statements in regard to the Commentary of Basilides lead to nothing.
Neither does it appear any more clearly what was the nature of the Gospel that Basilides wrote.