True meaning of ‘Appendix’

The passage below is from A History of the Index by Dennis Duncan.

Boyle against Bentley opens with some familiar hell-in-a-handcart rhetoric about the imminent demise of ‘Learning’ at the hands of modern editors and annotators. The preface also rehearses Alsop’s line that Bentley’s criticism is drawn from dictionaries, but takes this observation radically further by stating plainly that this is a wholly invalid mode of scholarship: ‘I am not therefore engag’d to defend [the Phalaris epistles’] Reputation against the Attacks of Dr. Bentley, or any other person, who, by the help of Leisure and Lexicons, shall set up for a Critic in this point’. In other words, anyone with a dictionary and enough time on their hands can find arguments to make about great literature, but these will be contemptible – inherently worthless – so there is no need to address them. It is an extraordinarily bold statement, but in case we were in any doubt whether Boyle and his cronies mean it, the claim is repeated liberally throughout the work. For example, ‘Dr. Bentley’s Appendix [i.e. the Dissertation] has all the Pomp and Show of Learning, without the Reality’. Bentley is accused of having only used indexes and dictionaries: ‘Dr. Bentley methinks should have dug deeper for his materials, and consulted Original Authors’. Finally, a pair of rather wonderful coinings sum the situation up: Bentley, accused of a purely mediated form of scholarship, is a ‘Second-hand Critic’, while his working method, reliant on reference works, is dismissed as ‘Alphabetical Learning’. But dictionaries are not, of course, the only sites of alphabetical learning, and the index comes under fire too, with Boyle (or whichever of his friends is ventriloquizing him at this point) stating, ‘I take Index-hunting after Words and Phrases, to be, next Anagrams and Acrosticks, the lowest Diversion a Man can betake himself to’.

‘Appendix’ has two different meanings, as follows:

1. supplementary material at the end of a text. 2. a part of human anatomy, a small tube-shaped part inside the body below the stomach, attached to the large intestine.

In this passage in question, I cannot decide which meaning of the two is suitable for Appendix in this context. My guess is the second meaning. Since the purpose of using that word is to dismiss Dr. Bentley, I thinks the latter is better that the former. And it is awkward to refer to a Dissertation as Appendix.

(Am I right?)

Thanks in advance.