This line was not in the first edition, but was added in the edition of 1828.
32, 252--*Behold! her bosom and half her side*, etc.

There exist at least three versions of this passage.

The text is that of the 1828 edition.

The edition of 1816 lacked ll.

255-61, having only these lines between 253 and 262: "And she is to sleep by Christabel.
She took two paces, and a stride," etc.
The third form is that of a MS.