Trying to merge subtree

gistfile1.sh

$cd /path/to/projectA
$git subtree split --prefix=subDirA/subDirB/ --branch=split-branch
.
.
Created branch 'split-branch'
334e51707eb9115be61f8a5bd731e7093d26742c
$cd /path/to/projectB
$git merge /path/to/projectA split-branch master
fatal: Can merge only exactly one commit into empty head
$git merge /path/to/projectA 334e51707eb9115be61f8a5bd731e7093d26742c master
fatal: Can merge only exactly one commit into empty head