You can get the same benefit of having a singly linked list with a head AND tail reference by:
- only keep a tail reference (no head reference)
- instead of having the last node in the linked list reference null, we have it reference the HEAD of the list, that is the beginning.

This is called a circularly linked list.  For example:

Singly linked list with head and tail:
head         tail
 |            |
---    ---   ---
 5 -->  2 --> 9 --> null
---    ---   ---

equivalent circularly linked list:
            tail
              |
---    ---   ---
 5 -->  2 --> 9 --|
---    ---   ---  |
/\                |
 |                |
 -----------------|

1. I claim that we get all the benefits of a head AND tail reference with a circularly linked list with only a tail reference.  Why?
2. What is the benefit of a circularly linked list over a singly linked list with a head and tail reference?