"It is quite worthy of notice, that although ">" is sometimes placed in the margin of the NT to point out quotations from the OT, and that too by the first hand, e.g. Acts 26:23; though more frequently by later scribes, as in Matt. 1:23; 2:6, etc. : this mark is never met with in the NT at the end of a line for the mere purpose of filling up a blank space (which is its usual purpose in the OT portion of Sinaiticus and some other MSS), except repeatedly in the leaves assigned to Scribe D, viz. 219 times in the other six leaves, four times in Rev.1:1—5 (see p. xvi). Elsewhere ">" is found in only four places which have suffered correction (Matt. 6:28 ; 22:9 ; Luke 11:36 ; 12:58), being used, like — in 1st Cor. 15:22, merely to cover erasures.
We must add too, that the few leaves of the NT ascribed by Tischendorf to Scribe D are much freer from itacisms, or instances of false spelling, than those on either side of them : the transition is quite remarkable from leaf 9 of A to leaf 10 (Matt. 16:9-18:12) of Scribe D, and then back again to leaf 11 of A, as the reader may see for himself by consulting our collation. These remarks, so far as they extend, would seem to suggest two scribes, A being identical with B, and possibly С with D ; the members of which pairs Tischendorf declares to be much alike; but whether the actual penmen be one, or two, or four, is of the less importance, as (in the N. T. certainly, and most probably in the Old) the whole work was clearly executed at the same time, and transcribed from the same older copy.
Moreover, the apostrophe ('), though frequently employed in the OT to divide syllables in the middle of a word, is never so used throughout the NT itself; while in the Shepherd of Hermas, at the end, assigned by Tischendorf to scribe B, we read: αγ'γελια, αγ'γελον, αλ'λα (3x), μελ'λοντες, πολ'λους, ελατ'τονι, εχ'μαλωτισμον , etc, and ">" several times at the end of lines. These minute points, insignificant as they may seem, go far to support Tischendorf's notion that the MS is the work of several distinct hands. (See also p. xxxii, note 7.)" (Scrivener, Sinaiticus Intro.)
Kirsopp Lake is also informative:
From all this, it would seem that the work of Scribe D was hardly in dispute, and well understood. It is naturally with some alarm then, that upon visiting the official Codex Sinaiticus Website, we find all the pages from 77-4 recto to 77-8 verso identified as "Scribe D" in the apparatus and titling above the photos."The discrimination of Scribe D from Scribes A/B is easier and admits of no reasonable doubt. There is a distinct difference in the script, though it is more easily perceived than described; possibly the letters are somewhat squarer in Scribe D than in A - the height being less in proportion to the breadth - and Scribe D is altogether prettier than A. But the decisive point is that Scribe D constantly fills out the end of a line with the sign >, which is rarely or never used by Scribes A/B."
Has there been a mistake by earlier critics with less access to good photos, or has the British Museum, custodian of the actual MS, made some remarkable blunder, based on a confusion between the end of the Quire and the 'cancel-sheet' (77-4 recto to 77-5 verso)??
The only sure guide would seem to be the quality of the text on the disputed pages.